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Thunderbird not saving sent mail

Posted on Jul 12, 2010 by Paul White

thunderbirdIf you find yourself in a situation where thunderbird is no longer saving your sent emails in the Sent folder, then I might have a solution.  In my case all emails from July 4th 2010 on were not showing.  That and anytime I clicked on my Sent folder it would take a very long time to load.  If any of these symptoms sound like your problem, then my solution should work.  Keep in mind by the time I got to this solution I had already gone through and deleted my .msf files, ran compact folders, and even created a new profile.  None of these solved the problem.  In short the problem was a bad email in my sent folder. The solution was to delete this bad email from the Sent folder then let thunderbird reindex it.  Now doing this is not easy.  You have to manually open you sent folder and find the bad email.  For those of you who don't want the history of this problem,  here is your quick and dirty solution

Solution: Thunderbird not saving sent mail

Open Thunderbird and take note of the most recent email in you sent folder ( this is your offending email )
Close Thunderbird.
Download the free 30 day trial of 010 Editor for Windows
Make of a copy of your Sent Data file from your Profile directory on thunderbird, and paste it to your desktop
Open your Sent Data file with 010 Editor
Find the starting and stopping address range of the offending email
Select this address range, and delete it.
Save your changes.
Recopy your Sent File back to your Profile Directory
Delete the Sent.msf
Open Thunderbird, and now all your sent mail is showing.

Causes of Thunderbird not saving sent mail

In my case I recently changed my mail server to handle up to 1 GB attachments.  This was to make it easier to send emails to and from my clients ( who are also hosted on my mail server ).  The problem was a 200 MB zip file I emailed my client.  Of course Thunderbird tried to save this email with the attachment to my Sent Folder.  Well I guess Thunderbird is not too keen on huge attachments.  That and my Sent folder was already 4.3 GB in size. 

I knew that this email was the cause because it was the last one that Thunderbird had record of being sent.  so I figured that logically the large attachment was causing problems for Thunderbird. So I had to delete it directly from the Sent data file.  Once I deleted it, I allowed Thunderbird to reindex the updated copy of my Sent data file, and all my emails could now be seen.  Hope this helps someone else out.  For reference I was using Thunderbird 3.1

UPDATE 7/21/2010
This problem happened again recently.  My theory was that maybe Thunderbird doesn't like large Folders. It just so happened that my sent mail folder was just a little over 4GB in size.  Unlike Outlook which uses a single PST file to store everything.  Thunderbird uses a individual file for each Folder.  But if you are like me and use a Global Local Folders to store all your email, and you have a dozen or so email addresses,  your sent Folder can easily get very large.  Turns out after some research that Thunderbird does have a Limit of folder sizes, and that Limit is 4GB.  The problem is once you go over this limit,  your email still get saved, but you can't see them.  This has to do with 4GB being the maximum addressed called by a 32bit software program.  And yes Thunderbird is only officially available as a 32bit.  There are some third party 64bit Builds of Thunderbird but I wouldn't trust them.

What to do if you go over 4GB for a folder size in thunderbird.

The problem is if you go over 4GB in size you won't be able to compact the folder, until you get the file size down to under 4GB.  In my case I was trying to get the sent folder working again.  so I listed out what I could see of my sent folder, and then sorted the messages by size.  I then started to delete the large emails that were not anything I needed to hold on to.  After doing this and deleting the sent.msf files from my profile directory.  I still could not compact folders.  So what I did was figure out the most recently email I could see in my sent folder.  Then using 010 Editor I searched for that email.  Then deleted the email after it.  Then once again I deleted my sent.msf file,and opened up thunderbird.  Now I could see all my sent mail.  I ran compact folders and the filesize of my sent folder dropped to 2.2 GB, and everything is working again.

Hopefully in the near future they will release a 64bit version of thunderbird that won't have this 4GB cap on folder sizes.  Even with this issue.  I would still take thunderbird over Outlook any day.

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jack | Jul 29, 2010 5:19 AM
Can I just delete the "Sent" folder? It is over 4gb. won't compact. I tried deleting the sent.msf.
paul | Jul 29, 2010 7:15 AM
You can delete it but only if you want to loose all your sent mail.  Else if you want to keep your saved mail you need to open it like i described above, and manually remove your larger emails.  The easiest thing to do is to search your sent folder for the emails with large attachments,  Then search for those emails with the 010 Editor, and remove them.  Once your sent folder gets below 4GB it will work again in Thunderbird.
Jack | Jul 29, 2010 8:02 AM
Paul, thanks. I appreciate your comment. I have deleted most of the e-mails in the sent folder. Of those I can view in the sent folder, I have less than 100 and they are all only a few kb, none have attachments. I think this started on when I deleted a large amount of old sent mails some with attachments. So now, after the sent folder opens I only see the 72 I have not deleted. Yet the sent file (no extension) in the profile folder is 4.2 GB. I looked at the program you mentioned and it looks to technical for me. So, to clarify, if I deleted that sent file (no ext.) will it reappear empty as the sent.msf file. So then I start anew with sent e-mail? Thanks.
jack | Jul 29, 2010 8:05 AM
Sorry, I was not clear in the above. If I delete the sent (no ext.) file it will reappear in the same manner as the sent.msf file reappeared when that was deleted. Thanks.
Jack | Jul 31, 2010 7:57 AM
Okay, I used the original suggestion and used 010 Editor. I worked. It took quite a while to load the large file. But after it did I was able to see the e-mails and delete. Other text editors could not open the large file but 010 Editor did. Thanks.
hubert F | Aug 26, 2010 10:00 PM
I had the same problem, and since I was skiddish about the 10Editor, I just archived EVERYTHING that was in the SENT folder and then deleted the SENT file (4.2 GB) ....hooray ...the problem is solved and everything is still in the Archive folders... ;-)  - thanks guys ...all the explanations above really helped to solve it...  ergo - 'archive' more often!
Tara | Oct 1, 2010 2:34 PM
Hello! I am on a Mac (OS X 10.6.4), is there an 010 Editor or similar to help me? I went through all my sent emails and have deleted all "unnecessary" ones with large attachments but the Sent file seems stuck at 4.39 GB. I want to be able to keep all my emails but understand if I can't keep all of them. If I put them in a subfolder (i.e. 2008, 2009, 2010) off the Sent folder will that be separate or contribute to the final size? I have gotten so used to being able to check my sent folder  but haven't seen what I've sent for the last week! I am slowly losing my sanity... Any help is appreciated, thanks!
runner43 | Oct 5, 2010 5:21 AM
pleas excuse my imperfect English.

To simplify matters I'll use this blog to show my problem which I couldn't solve up to now in several forums, even not with Google.

When I want to reply a mail by clicking on the answer-button the answer-window opens correctly but doesn't appear in the foreground but in the background.

I have two possibilities:
a) minimizing the mail-window
b) clicking on the tray-icon of the answer-window to be able writing the answer.

Maybe that anyone of this blog could help me.

Thanks in advance

Pietro | May 6, 2011 10:06 AM
After one day I realized that one day before I changed the system's clock and data, thus the e-mail that is sent were attached at Sent file but with a wrong data.... I work out by changing  the data of the last messages, they must be ordered chronologically in the Sent file, and deleting the Sent.msf.

Pietro | May 6, 2011 10:08 AM
sorry, I meant date not data.

Don | Jul 21, 2011 3:52 PM
I have a brand new install. I have nothing in my sent folder.
I have pop accounts.
I have set each account to use global inbox and to save sent messages in 'sent' in 'local folder'.

Nothing you have suggested seems to apply and nothing will make a sent email go into the sent folder.

Originally there was no 'sent' folder but after setting up my accounts and sending one the folder appeared...but it will not save any sent emails. It saves all sent emails in the inbox!

I realize this is a beta but from forum responses this is very simply a bug and needs to be fixed.

Is there a workaround that actually works?
Paul | Jul 21, 2011 4:06 PM
Don, on my setup here are the settings I am using on each of my POP accounts.
Tools -> Account Settings
then on left side under each account click on "Copies & Folders"
On right side there should be a box that says "When sending messages, automatically"
Check the box next to "Place a copy in"
check box "Sent" Folder on "Local Folders"
Click ok
Also make sure you are running the latest version of thunderbird which is 5.0 ( not the beta )
Hope this helps

Stefano | Oct 15, 2011 1:41 PM
I did a brand new install with 7.0.1 and also yet there is some problem with the folder/file size. I had to migrate 30000 messages from EML format (WLM) but if I tried to do it as one Thunderbird file it has failed. Also with two, four. Finally I needed 7 to do the work. At the end there were not any file over 4G. I am not so happy because of this limitation/bug. I think splitting is the temporary answer for this. Everybody should archive older mails and/or remove attachments. This is like Outlook with 2G limited pst-s. So poor technic!
Karen | Jan 15, 2014 9:37 PM

You nailed my problem. Just started happening this afternoon. I saw my Sent folder was over 3 gig. I deleted like mad, but it never seemed to be enough. Finally, I moved everything into a new Sent folder (Sent2), and my original sent folder was empty. Worked like a charm. Thanks to Thunderbird's excellent search functionality, I can still easily search the Sent2 folder along with everything else. MUCH appreciated. Keep this thread open -- people will definitely run into this over time if they don't delete stuff periodically. (Using Mac 10.6.8, Thunderbird user for many years - on version 24.2.0).

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