Thunderbird hangs forever when “Copying message to Sent folder”

I set up a new account under Thunderbird with an IMAP in-going and SMTP out-going. All mails and folders are correclty imported from the server. I received new mails can delete them (it is updated on the server). So everything looks good. However, when I try to send a new message, the message is sent correctly but while trying to save the mail in the ‘Sent’ folder, it hangs forever.

What is happening is that Thunderbird wants to save a copy of the sent message in a folder called ‘Sent’ which is located in the root of the account folders. If the folder does not exist, Thunderbird will attempt to create it. If it cannot be created, Thunderbird will hang until you cancel the send. In my case, this folder already exists so Thunderbird hangs forever.

One solution is to prevent Thunderbird to save the file since your server is already taking care of that action. So, you need to disable the client to save the file on the server but only locally:

    Tools –> Account Settings
    Select 'Copies and Folders' under your account.
    Look for the box that says 'When sending messages, automatically…' serve that there is a checkbox below it labelled 'Place a copy in…'
    Switch from "Sent folder on " + <you account > to the one below that says "Other" and select the "Sent" folder)
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77 Responses to Thunderbird hangs forever when “Copying message to Sent folder”

  1. Lisa says:

    Thank you. I was ready to toss thunderbird out the window but your solution was much easier and worked like a charm.

  2. jx says:

    I did it and didn’t help. I solved the problem by installing Thunderbird 13.0 Beta 4:

  3. Mike Robinson says:

    I was having this same problem. I had a local IMAP server with dovecot and TB accessed emails without encryption. Changing the “connection security” setting to STARTTLS seems to have solved the problem somehow. It used to happen randomly about every hour or so and the only way to fix it was to kill the thunderbird-bin processs and now I’ve been 3 days straight without this problem, sending probably 100 emails.

    • Amrinder says:

      This worked for me. Set account to STARTTLS.


    • Jeff says:

      This worked for, but I made the mistake of making the STARTTLS change in the Server Settings window. I found the next day, that I wasn’t downloading .any email. The change needs to be made on the Outgoing Server window, not the Server Settings window.

    • Jeremy says:

      It’s 2016, now—Thunderbird 38.5.1

      Would hang on first attempt to save to Sent folder. Clicking “Retry” would always be successful, but still annoying. Switched from SSL/TLS to STARTTLS (make sure you’re in the “OUTGOING SERVER” settings… not “Server Settings”, as Jeff pointed out) and it seems to be working much better, now.

    • Sanjeev B says:

      Thanks – this worked for me too.

  4. Hrishikesh says:

    Thanks a lot! It worked great.

  5. Jonathan says:

    It works but I want to keep a copy of sent files.
    to do this

    In thunderbird 15.01
    do sames as above – ie
    Tools>Account Settings.
    Select ‘Copies & Folders’

    check ; Place a copy in:
    and select ‘OTHER’

    This will now store the sent email on your hard drive/email folder, but NOT remotely in Yahoo / Gmail etc – but it does stop it hanging .

    • fred says:

      Some things never change: its now 2014/10, and my revision of TB is 24.6.0. And yes … it is (was ) hanging when copying ‘Sent Folder’. Your solution still works, and I thank you sincerely for that … cheers mate.

    • Dale says:

      This worked for me!! So many “decoys” out there for this problem!

  6. Christine Tobler says:

    Thank you, this problem has annoyed me for a long time. Your solution worked great!

  7. Jim Fletcher says:

    I have the same problem – but it only developed with latest TB update (17.0.4). I have tried all of the above suggestions and nothing works. TB is now essentially useless to me, as every Send takes multiple minutes to “Save to Sent Folder” (depending on size).

    • Tim Turner says:

      Same issue here, copying to SENT folder seems to have no effect… mine just hangs when sending for about 10 seconds. Changing SMTP settings has no effect. Very annoying. But I have 4 accounts and only one, which uses port 567 hangs, the others do not. I notice that Google SMTP settings uses port 465, Yahoo uses Port 465, Outlooks uses 587 and my server uses 587. Not sure why.

  8. Jemmy says:

    Thanks, this really helped!

  9. Same problem here with TM 17.0.4. I didn’t have this problem with previous versions of TB. However, it doesn’t always take the same time to save to the Sent folder. Usually less than a minute, sometime more, sometime instantly.

  10. bee says:

    I now have the same problem all of a sudden since TB automatically updated to 17.0.4. Suddenly I can’t send mail, it hangs indefinitely. Receiving is no problem. I can only send from my ISP on webmail. Ready to toss TB!! Does anyone have any other ideas?

  11. Riccardo Ronco says:

    thank you for the tip! it worked perfectly. Again, thanks.


  12. Bruno says:

    Had same problem on Thunderbird 17.05, mail was sent immediately but saving was problematic, so in “Copies/Folders I choosed to store in “Sent” under Local folders.

    Problem gone.

  13. I had the same problem in TB 17, but switching from STARTTLS to SSL/TLS seems to have solved it. I have no idea why, but the suggestions above helped, thanks everyone.

  14. I have been having this problem with TB not saving a copy to sent mail for a long time. It is definitely worse recently with 17.0.4 and its related releases. Storing the mail locally is not an option – you want everything up on your IMAP server so you can access email from anywhere.

    There is a related problem that TB loses connection with the server and can’t download messages.

    What can we do to have someone take a serious look at this? These kinds of problems really kill your productivity when you are doing a large amount of email with small attachments (less than 1M attachments). I am about ready to ditch TB and simply go to a web-based tool. I love TB, but these kinds of fundamental problems are unacceptable.


  15. Johnny says:

    Sorry to say, this did not work for me. I’ve had this problem for as long as I can remember using Thunderbird. This fix made it hang when trying to send instead and I was unable to send anything. Changing the settings back restored send functionality but back to the old hang on saving to sent folder. Thanks for the tip though.

  16. Andrei says:

    just choose “Other” in for store copies in Account Settings and choose the right label from your account (no typing, just click it)

  17. Cleo Cat says:

    FYI, I think I fixed this problem (it was intermittant here) by updating the settings in my imapd on the server.

    sudo vim /usr/lib/courier-imap/etc/imapd

    The MAXDAEMONS and MAXPERIP were set to 30, which was being exceeded every now and then, depending on how many people were checking their emails or sending stuff, since Thunderbird sometimes opens up multiple imapd connections and keeps them open.

    Updating those to ’60’ each fixed my problem. After doing “sudo service courier-imap restart” as well.

    Just wanted to throw in my two cents since I hadn’t come across that solution in my searches previously :).

    • Hector says:

      Hi Cleo,

      I think your fix works only in linux.. How can it be implemented in Windows.

      Thanks in advance for any help.

  18. rEEzA says:

    Thank you… Fixed my issue 😉

  19. rickv says:

    wow — thanks for this. FWIW, I use Icedove 17.0.9, and had to do both, switch where copies are saved and also use SSL/TLS, instead of STARTTLS. With only one of either, I still hanged, but now things are saving immediately after send. Cheers!

  20. Paul says:

    Thanks 🙂

  21. Thanks Thomas, this was a very helpful short and sweet tutorial! Thunderbird was quite frustrating for a while but this quick fix helped immensely. I set up a folder to hold these outgoing messages named local sent. The folder icon changed shape after the changes were made in account settings.

  22. Mario says:


  23. HJ Forman says:

    Works – thanks

  24. Michael Felt says:

    I do not think updating TB made a big difference. I had one account that worked fast, and the other one did not.

    The difference? In gmail folder settings that account with “show” Sent – I suspect specifically “IMAP/Sent” was the key difference.

    (Now if this was already suggested above – shame on me for not having read more closely the first time 😉 )

  25. Leon says:

    Thanks for this tutorial.
    Instead of selecting the sent folder of “Other” I unchecked Place a copy in:
    When I tested this with my Google account, the message did get stored in the Sent folder of Gmail.

  26. JC says:

    I just spent hours and hours trying to solve the problem : “TB displays a timeout error when copying a mail with big attachments to the sent folder”.

    Simply setting “Server settings > Connection security > STARTTLS” instead of SSL/TLS solved the issue.

    Thanks again

  27. RobD says:

    I have experienced this same problem. However, it turned out to be none of these issues.

    With mine, there was no security set up, so changing SSL to STARTTLS made no difference.

    It turned out to be one account, which was set to run on startup. There was clearly some problem with this account, because once I had changed the account that opened on startup of Thunderbird, I was able to send from all the other accounts without a problem. Interestingly, many using the same mail servers (different accounts though).

    It seemed to be something ‘blocking’ on this one account. Also, just with the Inbox, since I could log in to the webmail portal and send/receive/move messages about just fine. It was only with Thunderbird that got stuck when trying to view the Inbox and that in turn prevented ALL accounts from copying stuff to their Sent folders. Weird, for sure.

    I have yet to find what might be causing the block on this one Inbox. Works fine on webmail and other e-mail clients.

  28. Geoff says:

    Select the messages in your “Sent” folder and archive them. Wait for them to be archived, and the issue should go away.

    Using 24.6.0.

  29. I had the same problem with Thunderbird and my own Dovecot server. I fixed it by going to account settings and setting “Place a copy in” to other, then I selected the “Sent” folder manually (I knew it should be available since other clients have been able to see the messages). The Sent folder is now back and filled with messages from other mail clients I have used.

    Hope it works for you.

  30. Caleb says:

    Fixd! Thank You!

  31. c f yurkoski says:

    i had the same problem, i circumvented it by
    turning off copying to the sent folder completely
    and resorted to just CCing myself to save a copy.

  32. JIMB says:

    I think this may be due to synchronization. I turned off the “Select the folder for offline use” under Folder Properties for Sent and I have not seen any more hangups. This happened to me when setting up a new machine with a large Sent folder – it may have fixed itself after allowing time to synchronize.

  33. JSON says:

    I had the same problem but it’s solved now.

    By default, it’s to the “Sent” folder on youraccount@yourserver. This assumes that ‘Sent’ folder is there. If there is no ‘Sent’ folder on your server, TB will hang on.

    To avoid the problem, select ‘Other’, and then select an appropriate folder under your account such as ‘sent messages’. If you select a local folder, the sent message will only save in local storage.

    Hope it helps.

  34. Leo says:

    Hereby another solution not yet listed: disable idle command.

    Same issue: delays with Thunderbird (on Linux) while Outlook, web-based and iPhones go 10x faster.
    -irregular delay on loading folders e.g. inbox
    -huge delay on copying to sent folder

    Finally this worked for me:
    Account settings -> Server settings -> Advanced.. -> disable: Use Idle command if the server supports it.

    Good luck.

  35. Brandon says:

    The following fixed it for me immediately…. I noticed the folders in TB were not matching the web mail folders so researched ‘folder syncing’ issues. When I followed the folder syncing solution the sent message hang was no longer and all copies saved accordingly.

    harlanlax – IMAP not syncing all folders

    I am able to connect and get the entire Inbox perfectly but do not seem to get other folders. Isn’t IMAP supposed to allow all folders to sync?

    IS there something I can do to clear this up?
    Under Account Setting ->Server->Advanced uncheck subscribe only

  36. MarkLex says:

    I have this problem too with sent mail hanging. After Googling, I found out a solution that helped, but for some reason, the save doesn’t stay in server settings…….

    If you go to tools>account settings>server settings>advanced> and you will see maximum # of server connections to cache is on 5, change it to 1. That totally stopped my sent mail from hanging…….Problem is, it changes back to 5 on its own sometimes and I can totally tell because after a week of sent mail NOT hanging, it starts hanging again and I go to those settings and low and behold it’s back to 5..So I change it back to 1 and sent mail stops hanging again……..

  37. Fery says:

    Thanks a lot, it works like charm. I thought I’ll give up on Thunderbird, you just saved me 😉

  38. Randal says:

    My solution (IMAP) using a 32 bit Vista computer:
    1) Go to C:\Users\admin\AppData\Roaming\Thunderbird\Profiles\xxxxxxxxx.default\ImapMail (where xxxxxxxxx is the name of your ‘.default’ folder)
    2) Find the folder that contains your IMAP profile (not the .msf file), and delete the folder. This folder will be recreated automatically by Thunderbird (hopefully correctly to fix the issue)
    3) Close down your Thunderbird client, and all associated emails that you may be writing or have opened etc
    4) Re-Launch Thunderbird
    5) Send a test message from the account that was having the problem hanging after sending your message. It should now no longer hang anymore. That’s what resolved the issue for me.

    Thoughts but not tested (steps 6 & 7):
    6) ONLY IF IT IS STILL BROKE: If step 5 didn’t fix it, repeat steps 1 through 4, AND ALSO delete the .msf file

    7) IF IT’S STILL BROKE: Consider deleting your IMAP account in Thunderbird, close thunderbird and all opened emails etc. Then go back to C:\Users\admin\AppData\Roaming\Thunderbird\Profiles\xxxxxxxxx.default\ImapMail and delete the folder again & .msf file again, then relaunch Thunderbird and create the account from scratch.

    Hope this helps – has helped me a few times so I thought I’d share…

  39. Bazz says:

    Best way to solve it is just uncheck the “place a copy in…” the server still saves a copy, so making thunderbird do it as well seems pointless.

    I’ve been running mine like this for a month and it’s instant for sending and items still show in sent items.

  40. Dan says:

    Hi. I just ran into the same problem and the only way I could fix it was by right clicking on the Inbox folder and then on New Folder. Call the new folder Sent (I know there’s already one listed, but still, thought I’d try it.) Fixed it for me. Hope it works for you.


  41. Dan says:

    A Very Simple Solution I Discovered…

    Right click on Inbox, make a New Folder, call it Sent.

    This worked for me, I hope this works for you.

    Yes, I already had a Sent folder but this still worked for me, it doesn’t make a duplicate, I guess TB just needed to reset where the folder was, maybe it got a little confused at some point when adding my new email account.


  42. Daghan says:

    I have solved the problem with doing below, I use SSL/TSL

    1. Tools -> Account Settings
    2. Copies and Folders
    3. Switch from “Sent” folder to Other
    4.Select your mails Sent folder. For example Mine was -> Incoming -> Sent

  43. Nick says:

    For me it was the Windows Search integration that caused hangs on every send.

    This might be due to Windows 8 / 8.1.

    To turn the integration off:
    Tools > Options > Advanced (General tab) > Remove tick from “Allow Windows Search to search your messages”

    That’s all.

    • juan abba says:

      I use tbird 38.0 and windows 8.1

      cant find the parameter “tools>account settings>server settings>advanced> and you will see maximum # of server connections to cache ” as mentioned on following MarkLex entry.

      thanks in advance

      juan abba

      MarkLex says:
      February 19, 2015 at 5:14 am

      I have this problem too with sent mail hanging. After Googling, I found out a solution that helped, but for some reason, the save doesn’t stay in server settings…….

      If you go to tools>account settings>server settings>advanced> and you will see maximum # of server connections to cache is on 5, change it to 1. That totally stopped my sent mail from hanging…….Problem is, it changes back to 5 on its own sometimes and I can totally tell because after a week of sent mail NOT hanging, it starts hanging again and I go to those settings and low and behold it’s back to 5..So I change it back to 1 and sent mail stops hanging again……..

  44. Ed T says:

    Hey, good stuff. Thank you very much!!

  45. Mike says:

    I tried a number of fixes mentioned but none solved my problem:
    TB hangs after sending the message but before saving to the SENT message file. However, all returned to normal when I deleted a newly installed copy of System Mechanic Pro.

  46. Kazem Edmond says:

    Thanks very much. Your solution solved the problem for me.

  47. Same problem here. I just selected ‘show’ on IMAP sent folder in gmail settings. no problem now.

  48. timo says:

    I had same problem when I installed Linux with Thunderbird. There was no Sent folder and I had this error message when trying to send messages.

    I created Sent folder under “Inbox”. Next I clicked “View settings for this account” -> “Copies & Folders” -> “Place a copy in” -> change this to “Other” -> From drop menu choose your account – -> From drop menu choose “Inbox” -> choose “Sent” (folder you created).

    This worked for me. Now I could send messages and they were copied in Sent folder.

  49. Colin says:

    I had the same problem as the OP but my solution was the opposite. I changed the setting in the outgoing mail settings from STARTTLS to NONE and problem solved!

  50. Areeb Yasir says:

    I have the same problem with IMPAP but in Thunderbird 38.4 on Linux and it has been this way for years, it just seems that randomly it won’t copy to the sent folder.

    The sent folder does exist and always has but sometimes it fails copy. Sometimes Thunderbird will let you retry other times it will stay that way for hours unless you hit Cancel and then it will allow you to retry. Usually almost always retrying succeeds and works.

  51. Duke says:

    Feb 22 2016 and I started getting the dreaded ‘cannot save to sent folder’ message as outlined on this forum many many times. you would think after 5 years of reported issues, that a solution would have been created. Nonetheless, I had the issue and it took me a bit of fiddling, but I solved the issue and it works fine now.
    Not every problem is the same, but whatever was causing my problem was resolved by doing this:
    >Help>Restart with add ons disabled
    Done deal. Whatever add-on came with the download was buggy and caused this issue, because I did that and the issue was fixed instantly and all of my emails came though and sending was no longer an issue.
    Hope this helps some of you.

  52. john says:

    After accepting a security update to 38.6.0 on Ubuntu 14.04 I experienced this problem. Duke’s recommendation worked for me.

  53. Anonymous says:

    Perfect. Thank you

  54. AlexK says:

    Only 24hrs of testing but JIMB’s suggestion seems to be working. I’ve uncheck Sent folder for Offline Use.
    This can either be done in:
    Account Settings – Synchronization & Storage – Message Synchronization – Advanced and uncheck Sent
    Right click on Sent and go to Properties – Synchronization and uncheck Select this folder for offline use

    I’ve also set the server cache to 1 but I’m not convinced that was my problem.

  55. Pingback: Thunderbird Error Saving Messages

  56. Anonymous says:


  57. Paul Roberts says:

    I just had the same problem so googled it and found your post, the fact that so many people have commented proves that this is an on-going issue. In my case I set it to “Other”, selected my account (not Local Folders) then chose Inbox -> Sent – it now works a treat. Maybe the fact that my sent folder is a sub-folder of my inbox is what is confusing Thunderbird – I don’t know if this is a normal configuration but it seems they might need to make a tweak to Thunderbird if this is a quite common config.

  58. This problem seems to come and go. Here we are in 2018 and it has resurfaced. It takes a very long time to write the copy to your sendmail, so often you have to move on while this runs in the background.

    This morning I changed the Connection Security setting on Outgoing Server from SSL/TLS to STARTTLS for Google’s IMAP server. I noticed it changed the port number. This seems to have fixed the problem.

    Why wouldn’t Thunderbird’s default settings do this?

  59. Spud says:

    I’ve just fixed my version of this problem, having read all the above but not finding a solution. Had to create a new folder manually by right clicking on the email address on the left hand side of TB screen > New folder… > enter ‘Sent’ as the folder name, and create it under just the email address (not under inbox or anything)

    Now my sent emails are showing up in TB, webmail and on mobile app.

    Christ that was annoying, so glad i’ve fixed it!

  60. Archdeacon says:

    I had TB connected to my gmail account and the same message was coming up all the time. I tried switching off the keeping of a copy in the sent folder altogether and it appears gmail keeps the copy for me anyway. So no need to make thunderbird do the same thing. Simply disable the keep copy capability altogether. I do not know if this will work for servers other than gmail though so be cautious.

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