One small step for SL8TR

Here it is, the golden elixir :-)

Just kidding. This is the promised update, [I know, I know, promised long ago... yada yada.. I am sorry].

Its labelled version and includes MANY new features:

  • Improved - Background polling now does not consume many resources since it only looks at headers
  • Improved - Header search and replace is more consistent across platforms
  • Fixed - Many minor crash issues and formatting issues [from beta]
  • New - 3 configurable buttons with preset [configurable] time offsets
  • New - Keyboard shortcuts to preset buttons [ALT + 1, ALT + 2, ALT + 3]
  • New - Send Later Toolbar available
  • New - Send Later header visible in drafts folder [configurable]
  • New - Send Later column visible in drafts folder [configurable]
  • New - Awesomeness :-)

Send Later Prompt Screenshot

Send Later Prompt Screenshot - 3 Quick access buttons that can be configured as you like, with shortcut keyboard access using ALT+1,ALT+2,ALT+3

Send Later Preferences Window

Send Later Preferences Window - More preferences for people who like to tweak things till they are perfect

Send Later Configurable buttons

Send Later Configurable buttons- And the quick access buttons are configurable as well

So how do you get this awesomeness ? If you are already using a previous version, Thunderbird should prompt to update from this website, so you should be covered or you can try Tools -> Extensions / Addons [Right click and choose find update]. If you want to install it afresh then you can download it from here.

BTW, Send Later got featured in quite a few websites over the last couple of years and its time to thank them.

Send Later is download of the day on Lifehacker

Send Later is one of 10 must have extensions for Thunderbird

Watch out for more progress on this. If you have any troubles drop in a comment below and I will sort it out.




JacquesMarch 10th, 2009 at 19:42

Great extension and excellent update.
One problem: version 1.2 now conflicts with Display Mail User Agent (disMUA) extension 1.6.3 by preventing the display of user agent icons in the preview headers.
Where could the conflict be?

Karthik SivaramMarch 10th, 2009 at 20:04

Thanks for the report, let me try Display Mail User Agent and get back to you. Can you also let me know which version of TB you are running and what platform please.

ThomasMarch 10th, 2009 at 23:35

I have the same issue I had with previous versions: it only sends the delayed email if I navigate to another folder then return to drafts folder, otherwise it stays pending forever…

Karthik SivaramMarch 11th, 2009 at 00:15


Are you using IMAP ? What happens if you are in INBOX, Compose email, Schedule it for Send Later and then just stick around without any activity.

DirkMarch 11th, 2009 at 07:40

Hello Karthik,

Very well done, those were my (unmentioned) feature wishes you just added to the new release of Send Later, absolutely great.

This is like I see the option window, it is a bit lopped:

Is this extension still in the experimental stage?

May be this could be good:

To give the option to create / customize a new toolbar for “SendLater” (or display it like a calendar), the settings bar of SendLater is too long to be added to an existing toolbar (on my screen), it is lopped on the right side then. And the “Send later” button of – I think it is MagicSLR – doesn’t work anymore, clicking it nothing happens.

Some scroll down menus are too long, you have to scroll down first when you choose some dates, before you can click the time / date / day, so may be making it like that wouldn’t be bad:

Before the update today, Send Later – I don’t know why – suddenly didn’t work anymore, without that I have changed any settings by purpose. Do you have any idea, what the cause might have been?

I am very pleased about this new release, many thanks.

Nice greetings, Dirk

Karthik SivaramMarch 11th, 2009 at 10:10

Hi Dirk,

Thanks for your report. From initial impressions I think the clipping issues etc you see might be related to the the theming component that you are using [either in thunderbird or in Windows XP]. Could you please disable the theme [or something like WindowBlinds ?] and check whether the issues still exist ?

Cheers, Karthik

Jeremy BurgessMarch 11th, 2009 at 12:02

I desperately need this update so I can use thunderbird instead of outlook. The old version didn’t work but it didn’t crash thunderbird, just slowed it down.

So I thought maybe it was my exchange server (yes, I was able to figure out how to get the exchange server to work with Thunderbird, no thanks to microsoft) so I completely uninstalled ALL of thunderbird (not that easy to do by the way).

I then reinstalled and only used my gmail (imap) with thunderbird and NO ADDONS what so ever.

As soon as I installed, it crash thunderbird. No error, just freezes and never moves.

So, I unintalled again, installed my favorite add ons (lighting, google contact, contacts sidebar, provider for google calendar so it auto sync) just to see if that would work.

It still failed (freezes up with no error and goes no where).

I’m running XP sp2 on a toshiba that is less than 6 months old.

I hate outlook and I love thunderbird but I need my send later capability.

I may have to switch back.

Please help.

Karthik SivaramMarch 11th, 2009 at 14:00

Are you having issues with version or the previous version ? I havent tried a gmail IMAP provider with this version, I will try that if you are having issues with version


MairaMarch 11th, 2009 at 20:06

Many thanks! Previous version never worked on my PC so it’s been disabled for more than one year awaiting for this release. Now it works wonderfully for POP accounts but my IMAP account (not Gmail) makes Thunderbird freeze. It’s ok for me, that account is a personal one so I won’t need SL8R functionality on it, but maybe I can help you debug this.

DirkMarch 12th, 2009 at 00:39

Hello Karthik,

Would you mind dwelling on my subjects, questions? I would appreciate it very much and be very glad.

Nice greetings, Dirk

Karthik SivaramMarch 12th, 2009 at 01:31

Hi Dirk,

As mentioned above, I would like you to disable the theming software you are using and check the look. I have also sent you an email to this effect, please let me know how you go.


[...] or letting you disguise your late-night email checking. Version 1.2 of Send Later incorporates a few other fixes and goodies, including a toolbar and draft folder presence and reduced memory use. It’s a free download, [...]

[...] or letting you disguise your late-night email checking. Version 1.2 of Send Later incorporates a few other fixes and goodies, including a toolbar and draft folder presence and reduced memory use. It’s a free download, [...]

J. MuellerMarch 12th, 2009 at 04:40

Am I correct in thinking that send later won’t work if I shut down my laptop or close thunderbird? It’s always nice to delay the sending of an email to a boss until later in the evening… it looks like you’re burning the midnight oil.

PerryMarch 12th, 2009 at 06:07

I installed it today, and it does not work. All messages I try to send later end up in the “Unsent” folder in the “local folders” (which I do not use).

Karthik SivaramMarch 12th, 2009 at 12:51

@J. Mueller,
Yes you are right, it will not work if you exit thunderbird or close your laptop down, since it is a client side extension. I have had reasonable success using an IMAP account and thunderbird with sendlater running on a PC as well as my laptop where the PC just monitors and sends [obviously there are issues when both are running and the time clashes], but its a reasonably complicated affair.

Thunderbird works by scheduling email for later delivery by putting emails in Drafts and then moving them to Unsent and delivering them. There might issues with the delivery like password required or some other dialog popping up when the delivery actually takes please. Can you contact me if you are still having issues and are willing to help me debug ?

Jeremy BurgessMarch 13th, 2009 at 00:59

The previous version never worked for me but the newest version crashes thunderbird.

I set it with an exchange server and that crashed as well.

I don’t use pop email anymore.

Is that what you tested it with?

Karthik SivaramMarch 13th, 2009 at 01:16

This version has been tested with both POP3 mailboxes and IMAP mailboxes on Mac OS X 10.5 / TB and Windows Vista / TB and Ubuntu Linux 8.04 / TB The POP3 is an exchange server and the IMAP is a hosting provider’s IMAP system. I am really interested in solving your issue could you please contact me by email so that I can get some more debugging information from you.

My email address is my first name at this site.

GeorgeMarch 13th, 2009 at 10:27

I installed it yesterday around noon and set up 6 test email, 15 mins, 2 hours, 4 hours and 2 email to be sent the following day, (this morning at 5:00 am, approximately 17 hours after I installed the extension) and everything worked flawlessly. But, like Jerermy when I now open Thunderbird it just hangs with the following warning message:

“As script on the page may be busy , or it may have stopped responding. You can sop the script now, or you can continue to see if the script will complete.”

At this point I am offered “Stop Script” and “Continue”, but the program is frozen.

I have completed the following steps.

1. Thunderbird works fine
2. Installed the extension – Thunderbird freezes
3. Uninstalled the extension.
4. Reinstalled the extension. – Thunderbird freezes
5. Uninstalled the extension.
6. Downloaded the extension again
7. Reinstalled the extension. – Thunderbird freezes
8. Uninstalled Thunderbird
9. Reinstalled Thunderbird
10. Reinstalled the extension – Thunderbird freezes
11. Uninstalled the extension – and this took some very fast mouse clicks (I have determined that I have a window of about 8 seconds to uninstall the extension before Thunderbird freezes.)
12. Thunderbird works fine.

My setup
I use gmail – plain and simple no fancy add ons
Hp Laptop
Windows XP sp2
Thunderbird TB
Thunderbird Extensions
Canadian English Dictionary
Toolbar buttons

I am not a techie and maybe I have provided too much information and I apologize for that. I hope this helps with your analysis.


Emily PMarch 13th, 2009 at 17:44

this is just what I need.. but I’m getting the error:
“send later will not be installed because it does not provide secure updates”

JacquesMarch 13th, 2009 at 20:49

Hi Karthik,

I’m using Thunderbird version (20081209) on Windows XP.
SL8TR 1.1.5 has no conflict with Display Mail User Agent (disMUA) 1.6.3, but version 1.2 prevents the display of user agent icons in the preview headers.
It’s not a great problem, but you know how one get’s used to one’s favourite extensions!
Other than this small conflict, your extension works perfectly.
Compliments for the good work. SL8TR is definitely a “must-have” Thunderbird extension.

Karthik SivaramMarch 13th, 2009 at 20:51


There is never too much information :-) Let me look into replicating the issue.


Karthik SivaramMarch 13th, 2009 at 20:54


This has something to do with signing updates. Let me investigate this further and get back to you.


Karthik SivaramMarch 13th, 2009 at 21:00


Could you please let me know which version of Thunderbird you are using ?


[...] or letting you disguise your late-night email checking. Version 1.2 of Send Later incorporates a few other fixes and goodies, including a toolbar and draft folder presence and reduced memory use. It’s a free download, [...]

PerryMarch 14th, 2009 at 06:49

@Karthik: I ran a few more tests, and everything seems to be working today. Thanks for the offer of help!

AlessandroMarch 16th, 2009 at 17:15

This is a great update!
Just wondering if you’ve looked into the conflict with Display Mail User Agent?

Karthik SivaramMarch 16th, 2009 at 23:53

Hi Alesandro,

I am looking into the issue as well as a couple of other things. I am also looking for a few guinea pigs to test the next version, let me know if you are interested.


AlessandroMarch 17th, 2009 at 01:10

Hi Karthik,

Thanks for your feedback. Considering the usefulness of SL8R, I would feel guilty if I didn’t accept being a guinea pig. ;-)

Mind you, in that case, could I suggest that the status bar message be hidden UNLESS there are pending e-mails to send later?

ThomasMarch 17th, 2009 at 02:56

Tried to install on TB I have some POP and some IMAP accounts.

I get: … [TRYCREATE] Mailbox does not exist.

DirkMarch 18th, 2009 at 22:14

Hello Karthik,

A very adversarial behaviour (according to the way I would like to use this great extension) is: when you open an e-mail you already specified (e.g. yesterday) a send later date (e.g. on 12.09.09) to edit (what I do often) and then save it (and then close the compose window with e.g. “Ctrl + F4”) the specified date is disappeared, so the e-mail obviously would stay in the draft folder not being sent.

It would be good for me just to save and have the send date kept like it was.

Very nice extension.

Nice greetings, Dirk

DirkMarch 19th, 2009 at 03:34

Hello Karthik,

And why is it, that in the status bar, SL8TR [PEND X] often shows an amount which differs from the actually pending e-mails, e.g. there are three e-mails pending and shown are 22 or after some time 9 etc.?

Often the pending e-mails are sent some time later than specified, why is that? It often seems to be, just when clicking the folder “Drafts”, that then they are sent immediately.

Nice greetings, Dirk

DirkMarch 19th, 2009 at 21:24


Sometimes or always on my system the pending e-mails seem to be sent only after clicking the folder “Drafts” after the determined date. When just clicking the folder (anytime after the determined date) they are sent immediately.

Nice greetings, Dirk

Karthik SivaramMarch 20th, 2009 at 14:10


When editing a previously scheduled message, just choose to send later again [instead of ctrl+F4]. It will show you the same time again, just proceed.


SreevathsaMarch 20th, 2009 at 23:34


Thanks for the extension. I have TB with an IMAP account. The extension just doesn’t work on this setup. After I hit [Ctrl + Shift + Enter] in the compose window, I get the pop up asking me when to send the message. I tried the following with difft messages:

1. Setting the time option
2. A self-predefined 2 min, 5min delay option

After this, the message is saved in drafts folder but never got sent at the specified time.

FYI, (if it matters)

1. I have a few other/old composed but unsent messages in my Drafts folder.
2. I use NTP server to sync my system time

If you want me to post any logs or need other information, please me know.


SreevathsaMarch 20th, 2009 at 23:39

BTW, missed mentioning my platform. Fedora Core 10 on x86.


DirkMarch 21st, 2009 at 23:28

Hello Karthik,

Many thanks for the explanation, that was my thought also to do it like this, but it seems to be a bit error-prone for me, so if you press “Send” accidentally after editing, then…I used Outlook before and when set a send date this date kept set after editing / saving again.

What do you think about this:

And why is it, that in the status bar, SL8TR [PEND X] often shows an amount which differs from the actually pending e-mails, e.g. there are three e-mails pending and shown are 22 or after some time 9 etc.?

Often the pending e-mails are sent some time later than specified, why is that? It often seems to be, just when clicking the folder “Drafts”, that then they are sent immediately.

Sometimes or always on my system the pending e-mails seem to be sent only after clicking the folder “Drafts” after the determined date. When just clicking the folder (anytime after the determined date) they are sent immediately.

Nice greetings, Dirk

lynedMarch 24th, 2009 at 07:53


MarkMarch 24th, 2009 at 11:34

I can confirm that this causes Thunderbird to Hang. Well, at least it takes too long for me to wait, and I am forced to quit it and restart.

I have ZoneAlarm, and have found that while it is hanging, ZA’s vsmon.exe is taking up a lot of CPU time. I understand that vsmon.exe is supposed to scan email, and TB does indicate that it is downloading a message while it is hanging.

Turning of ZA didn’t help.

I have TB

Pity. I was looking forward to using this extension.



Martin D.March 25th, 2009 at 05:01

Hello Karthik,

Nice Add-on!! But there is one problem: It also polls my imap-accounts. I would appreciate an option to disable this. For now (and the previous version) i just out-commented the whole imap-part in the backgrounding.js, ln. 357..377.
My reasons for this: a) using imap produces an error-box on every run because one of my imap-accounts works only over an ssh-tunnel which does not exit most of the time.
b) i don’t like the traffic created by this. Maybe a server-operator might detect the usage of SL8TR …

Kind regards.

LeopoldusMarch 26th, 2009 at 02:20

Hello Karthik,

Your SendLater would be the most useful extension for Thunderbird what I have been missing for the last 2 years… If it would only work. But it does not do anything (Windows XP SP-2 / TB / many IMAP and some POP3 accounts). I’ve tried Send Later with IMAP and Pop3 accounts, but the result is the same: all postponed messages just stay in my local folder “Drafts” forever, even when I go there and press key F5 to renew the folder’s list.

After I’ve installed Send Later and restarted Thunderbird, I’ve got the following error message:
“Alert: The current command did not succeed. The mail server responded: Mailbox does not exists, or must be subscribed to..” (can send you a screenshot). I closed it, but it keeps popping every 6000 ms (or another time interval as set in SendLater’s settings to check the folder).

BTW, when I look at the postponed message’s header in the folder “Drafts”, I don’t see there anything special I supposed to see (eg some special X-tag).

Could you advise me anything? As scheduled sending is one of the most important functionality for me, I will be VERY appreciated for the help.

mirantraMarch 26th, 2009 at 06:46

Hola, instalé la extensión Send Later en thunderbird en Ubuntu 8.10 Intrepid Ibex sin embargo no manda nunca los correos. Está configurada y todo en orden pero al mandar los correos, por ejemplo, con 15 minutos de retraso, nunca llegan a destino. Tengo una cuenta de Gmail en Thunderbird con IMAP. ¿Qué pasará?

Saludos y gracias

Karthik SivaramMarch 27th, 2009 at 00:18


Since Send Later scans the drafts folder, if your drafts folder is held on the server (IMAP) then it would keep retrieving the emails from the server. A simple workaround is to set your drafts folder to be held locally. Please try this and let me know.


Karthik SivaramMarch 27th, 2009 at 00:19


A simple work around would be to have your drafts folder local. But, your suggestion is good and I will try to incorporate into either the next version or the version after that.


Karthik SivaramMarch 27th, 2009 at 00:23

HI mirantra,

I believe you are having issues with Send Later and Gmail account, there have been reports of issues with this kind of setup and I am investigating it for the next beta version. Please stand by.


Karthik SivaramMarch 27th, 2009 at 00:26

Hi Sreevathsa,

Is your IMAP account from GMAIL [there have been some issues in this setup]. Also, could you tell me if you get a [PEND 1] message in the status bar. If you do not get this and just see a SL8TR IDLE message then can you shift your draft folder to local folder and try again.


DirkMarch 27th, 2009 at 22:32

Hello Karthik,

I would be very glad, if you see a chance to answer and I would appreciate it very much.

Can I avoid happening this:

And why is it, that in the status bar, SL8TR [PEND X] often shows an amount which differs from the actually pending e-mails, e.g. there are three e-mails pending and shown are 22 or after some time 9 etc.?

Often the pending e-mails are sent some time later than specified, why is that? It often seems to be, just when clicking the folder “Drafts”, that then they are sent immediately.

Sometimes or always on my system the pending e-mails seem to be sent only after clicking the folder “Drafts” after the determined date. When just clicking the folder (anytime after the determined date) they are sent immediately.

Nice greetings, Dirk

Jim HeardApril 1st, 2009 at 14:29

Hello Karthik,

First, a quick reply to one of Dirk’s questions:

“And why is it, that in the status bar, SL8TR [PEND X] often shows an amount which differs from the actually pending e-mails, e.g. there are three e-mails pending and shown are 22 or after some time 9 etc.?”

Dirk, every time you click into the “Drafts” folder, SL8TR scans for pending messages. It does not differentiate between messages already scanned, and new ones added since the previous scan. Thus, the [PEND X] count will increase, sometimes to an alarming level. This continues as long as you remain in the Drafts folder. However, SL8TR will NOT try to send that many messages - the only inaccuracy is in the number in the [PEND X] display. To resolve it, just select a different folder (get out of the Drafts folder) and wait for the next scheduled check by SL8TR. It will automatically correct the count and update the display.

I’ve been using SL8TR since last October with no significant issues until now. However, v1.2.0.0 has introduced a major headache for me.

I preload email messages for a limited group of recipients, as much as 2 months in advance of the actual “Send” date. After installing v1.2.0.0 I am unable to set the correct month; if I select April, SL8TR changes it to May; June is changed to July; September changes to October; November changes to December. I shifted to 2010, and found the same discrepancies; in addition, February becomes March. From what I see, the other months behave properly.

I have uninstalled and reinstalled SL8TR several times, with no change in the behavior. If I have time in the next day or so, I’ll do a clean install of Thunderbird on another computer, with only SL8TR, and report the results to you.

The only way I can preload my messages now is to customize the shortcut buttons; since they’re a new function (and I like the concept), I’ll test them to see if they’ll provide an acceptable workaround for the issue with the months. Did you test the buttons with an extremely large number of minutes? Is there a limit on the number of minutes I can set? Right now I’ve set the buttons for 6 hours, 24 hours, and 26 hours, with test messages waiting. I’ll report the results as soon as they’re in.

I will gladly email you screenshots or anything else which might help you troubleshoot this issue.

WinXP Pro SP3
multiple POP accounts on my own domains - no IMAP, no Exchange

JimApril 1st, 2009 at 17:44

Hello again Karthik,

I installed Thunderbird with only SL8TR on the second computer, and my initial review indicates everything is working properly. I’m still testing, but for now, perhaps you should edit my previous comment to remove reference to the issue, so as not to confuse anyone else.

Thank you for creating SL8TR. Prior to this recent issue, I had experienced only minor unexpected behavior, with easy work-arounds. It performed flawlessly with messages sent as much as 60 days after original composition. I look forward to regaining that level of reliability and functionality. I also really like the shortcut buttons on the toolbar - excellent work!


JimApril 3rd, 2009 at 08:54

Hello Karthik,

UPDATE: SL8TR is working fine on the original computer now, after I disabled several other Thunderbird extensions (Correct Identity v1.3.1, Custom Buttons v2.0.9.10, CuteMenus - Crystal SVG v1.9.3, and Mr. Tech - Gant Icon Pack v1.0.3). I had installed those awhile back out of curiosity, but didn’t need any of them, so I don’t miss them at all. The functionality of SL8TR is far more useful and important to me, and everything seems to be working “as advertised” now.

I’ll continue testing to try and identify which of those extensions was causing the problem. I’ll email you with those results.

I’ll also be happy to assist you with beta-testing, if you like.


SlyApril 4th, 2009 at 08:41

Great extension, but I have noticed two problems:

1) When using SL8TR to reply or forward a message the little icons next to the email never appear. So even after sending the email there is no way to see that your responded to an email (besides checking the sent folder). Is there any way you could fix this?

2) When adjusting the date, time, etc. for sending a message the dialog boxes get cut off. Please make the SL8TR box bigger or have it dynamically resize to display all the dialog boxes.


DustinApril 7th, 2009 at 19:43

this plugin causes my thunderbird to crash a little bit after opening. I am using thunderbird 2.0

David FinleyApril 8th, 2009 at 17:30

For Emily P Mar 13: that message was emitted by Firefox - I got the same message when I clicked on the download link because Firefox took it to be a Firefox add-on. If you instead click the mouse button to get the menu including “save link as” you can save the file to your hard drive. Then select add-ons from the Thunderbird Tools menu to install it.

David FinleyApril 8th, 2009 at 18:38

I have my own problem - drafts don’t get sent. I installed SendLater on Firefox for Solaris 10 x86.

The error message I get is:
Error: uncaught exception: [Exception... "Component returned failure code: 0x80520015 (NS_ERROR_FILE_ACCESS_DENIED) [nsILocalFile.create]” nsresult: “0×80520015 (NS_ERROR_FILE_ACCESS_DENIED)” location: “JS frame :: chrome://sl8tr/content/backgrounding.js :: CheckThisURI :: line 245″ data: no]

Same error with Thunderbird

Lines 239-245 of background.js are:

var dirService = Components.classes[";1"].getService(Components.interfaces.nsIProper
var tempDir = dirService.get(”TmpD”, Components.interfaces.nsIFile);
var tempFileNativePath = tempDir.path + “\\” + “tempMsg” + messageHDR.messageId + “.eml”;
var sfile = Components.classes[";1"].createInstance(Components.interfaces.nsILocalFile);
if (sfile.exists()) sfile.remove(true);
sfile.create(sfile.NORMAL_FILE_TYPE, 0600);

Per the truss output, the escaped backslash in the tempfile path setting is the culprit:
/tmp\tempMsg49DC38F7.2080109@xxx.yyy.zzz.eml is given as an argument to successive failed xstat and open64 calls.

Needs some logic to handle Unix/Windows differences.

Karthik SivaramApril 8th, 2009 at 23:36


Thanks a lot for that extensive debug info, I will handle this in the next version. I haven’t had a chance to test with Solaris, so I might bounce the next version off you, if you don’t mind.


David FinleyApril 9th, 2009 at 07:45


If that backslash in the tmp file path is the only problem, could I not just change that to a forward slash (only instance I found), and, if you could provide the manifest file, rebuild the jar file, since I extracted the other components via ‘jar x’? Or you could make a quick compilation with just that change, for me to try?

DirkApril 9th, 2009 at 09:12

I have intensively tested SendLater for some time now and tried to use it on a productive system and it unfortunately turned out to be unusable for me, it works absolutely unreliably for me.

Might there be a way generally to make it work reliably somehow? Are there some settings I might miss or anything else?

Many thanks for you great help.

Nice greetings, Dirk

AlessandroApril 13th, 2009 at 13:12

Hi Karthik,

Any news about updates, especially regarding incompatibilities with other add-ins?
If you need a beta tester, please count me in.
In any case, thanks for the good work.


[...] or letting you disguise your late-night email checking. Version 1.2 of Send Later incorporates a few other fixes and goodies, including a toolbar and draft folder presence and reduced memory use. It’s a free download, [...]

JimApril 17th, 2009 at 12:21

Karthik, I’m perplexed at all the issues others are experiencing. My installation of SL8TR on Thunderbird v2.0.0.21, on a WindowsXP Pro production machine which is in use 24/7, has been working flawlessly since my previous posts. I have a second installation of Thunderbird v2.0.0.21 on a second WinXP Pro machine; that instance has fewer extensions, but includes SL8TR. What information can I provide from my system(s), for comparison with the others in an effort to resolve the issues?

While I *am* a geek, I’m not a programmer. If I can help in any way, please contact me privately via email.

AlessandroApril 20th, 2009 at 13:40

FYI (from the author of dispMUA. Received this evening):

Alessandro Fontana schrieb:

> > The latest version of the SendLater extension (1.2) prevents dispMUA
> > from showing user agent icons in preview mode (it doesn’t effect the
> > icons when one opens the e-mail). The previous version of SL8R (11.5)
> > didn’t have this incompatibility.
> > I have signalled this to the creator of SL8R, by the way; but do you
> > have any idea where the problem might be?

That’s simply bad programming. Not mine. :-)
The addon must insert themself into header display routine. This can be
done safe or it can be done as a fast and dirty hack.

Karthik SivaramApril 20th, 2009 at 17:01

Thanks Alessandro.

I believe this is fixed in the next version. Let me know if you want to be in the beta.


AlessandroApril 21st, 2009 at 04:36

Hi Karthik,
Sure, I’d be pleased to be in the beta.
When do you think you’ll release it?

RobinApril 21st, 2009 at 15:25

Holy cow, I’ve never seen email like this. Thunderbird blows outlook off the shelf, and I only discovered this after I needed delayed delivery that actually worked. Awesoime add on, and Thunderbird has a new user.

MichaelApril 24th, 2009 at 09:58

Dear Karthik,

thanks for this addon. I love it. Is there any possiblity to make it work with the TB3 beta? Is the send later beta already working with TB3 beta?

Regards, Michael

VermontEngApril 25th, 2009 at 07:30

This looks like a great idea - however, when I installed the latest version on TBird - latest release as of 4/24/09 - it locked up. Oddly, it locked up so hard that I can’t even uninstall the plugin to see what is wrong. Any quick ideas on how to manually unistall a plug-in without being able to run T-Bird?


VermontEngApril 25th, 2009 at 07:47

Oh, sorry - should have checked MozillaZine - C:\Documents and Settings\\Application Data\Thunderbird\Profiles\ and remove the sl8tr directory under the profile. Then all is well again….

But it’s odd - perhaps other plug-ins are conflicting with it? Seems a shame as it looks like a fantastic idea!

denaliApril 29th, 2009 at 04:59

This has probably been asked before but is there any chance we can have the option of putting the custom buttons (15 minutes, 30 minutes etc.) on the toolbar without the default Send Later button with the clock, calendar et al? They take up far too much screen space if you’re not using them, and I much prefer buttons to keyboard shortcuts.

I’d like to put a “Send In 5 Mins” button on the toolbar in place of the default Send button but the clock, calendar etc. push all my other buttons so far to the right that either I lose them off the side of the window or I need to make the window so ridiculously wide that the 72-column wrapped fixed-width message text looks tiny all cramped into the left half!

Otherwise this is an excellent add-on. I’ve yet to see any of the issues others are reporting. I had one or two crashes when setting the initial options (possibly caused by other, unrelated messages in my Drafts folder) but it’s been rock solid since.

slengfeApril 29th, 2009 at 21:19


Great, version is now working with my (German) version of TB (version 1.1.5 wasn’t). There is still one problem: SendLater tries to connect to my IMAP-Account while starting TB. If there is no internet connection at that moment, TB crashes and is not accessible at all. Since there is no chance to avoid this, I had to deactivate SendLater again when I use TB offline.


JimMay 3rd, 2009 at 12:06

VermontEng, if you scroll back up the blog a bit, you’ll see where I had a problem with some other extensions conflicting with SL8TR. I disabled them, and all’s been perfect since then. Since I wasn’t using those other extensions anyway, I uninstalled them - you may want to try disbling things until the issue is resolved, then try re-enabling one at a time to see if you can identify the specific culprit. Restart TBird each time, of course…

GeorgMay 4th, 2009 at 04:39

I get the “Mailbox does not exist” error, then thunderbird freezes. Tried with 1.20 and 1.1.5

LeopoldusMay 5th, 2009 at 04:22

Hello Karthik,
Could you advise me anything regarding my post from March 26th, 2009 at 02:20.
Thanks in advance!

FrançoisMay 8th, 2009 at 19:53


Send Later seems to be a very useful extension. However, I have some trouble using it: I get a message telling me “Send Message Error” (See picture at ).
How comes Send Later cannot use this smtp server, while I use it without a problem when I manually send my message?

Thank you if you can help me.

Karthik SivaramMay 9th, 2009 at 17:03

@Leopoldus, please send an email to softwarebeta . Let’s get to the bottom of this, [it might help if you try a new user account/profile and have only a couple of mailboxes in it to check].

@Francois, There seems to be some error in sending the email, this might be due to wrongly configured “default smtp server” or maybe your smtp server requires mail check before send, OR [and this is the most common case], you do not have password saved for this account [you will normal ly get a password prompt in this case]. Please let me know if you are able to solve the issue.

FrançoisMay 11th, 2009 at 19:02

Thank you Karthik for your quick reply.
The default smtp server is the one I normally use to send email. It is a gmail account and I have configured it as suggested by google ( ). The password for this account should be saved, since I never type it when I use TB (well, i have typed it once when I installed thunderbird, of course).
It might be that gmail’s smtp server requires mail check before send, but then I don’t know what to do.

Best regards. François.

LeopoldusMay 12th, 2009 at 02:20

Thank you, Karthik! I’ll try to test it at a new pure TB user profile.
But I’m not sure what is “softwarebeta”? Is it your domain? What is the full e-mail address?

PatrickMay 12th, 2009 at 18:58

How can I display the “Send later preferences” window ?

Thank you in advance for your reply.


PaulMay 25th, 2009 at 15:29

Hi, Love the concept. Just switched from Eudora 7 in which I used this feature all the time. However as soon as I installed Send Later 1.2 on the lateset version of TB (2.00.21) I started getting “Connection to server timed out. PLease help as I now can’t get any mail.

Leave a comment

Your comment