Okay a specific post for those who use Thunderbird as an email client.   Basically I had some issues with my brand new PC where it BSOD (Blue Screen Of Death) almost immediately (turned out to be a loose fan in the tower!).   Upon fixing the PC I could open Thunderbird but not see any folders in the Folder Pane on the left.

So here’s the solution (I used the error console in Thunderbird to search for a possible solution):

  1. Navigate in Windows to the your Thunderbird profile folder (e.g. “C:\Users\YOURUSERNAME\AppData\Roaming\Thunderbird\Profiles\SOMETHINGHERE.default)
  2. Find the file “folderTree.json” back it up first and then delete it (or just rename it OLDfolderTree.json)
  3. Now load up Thunderbird, your problem should have been fixed (it seems to create a new file)!

SOURCES (this conservation helped me) : https://bugzilla.mozilla.org/show_bug.cgi?id=707329



  1. It was a nightmare when my foldertree simply disappeared (I use TB under Ubuntu linux). I found the folderTree.json easily and did as you advised. It worked. Thanks a lot!

  2. tried it – didn’t work – then I tried deleting session.json as well and folders were then when I next started TB – worth a try if deleting foldertree.json doesn’t work.

  3. Dear Moderator, Please cancel my last post as TB is back to its old tricks – still looking for a solution.

  4. For those after trying the above method and failed. This is what i did.

    1. Backup using MozBackup
    2. Uninstall thunderbird and delete the whole thunderbird folder in the roaming folder
    3. Reinstall thunderbird and setup 1 account
    4. Restore profile using MozBackup and select just the general settings, emails and bookmarks. Do not restore the extension.
    5. Everything is back to normal

  5. Thanks for sharing your experience. Unfortunately that didn’t work for me, even though the symptom was the same as yours:


    Here is what worked for me:
    1) Make a BACKUP COPY of your profile folder in %appdata%
    2) Delete any .msf file in the profile folder and its subdirectories. Iin my case, for some reason I had more than 10.000 of these files! The problem seemed with these INBOX-####.msf where #### are variable numbers. The solution was running a del /s *.msf (pay attention to executing the command JUST IN THE PROFILE FOLDER of course, not in the backup folder or in any other higher level folder).
    3) Open Thunderbird and let it rebuild its indexes.

    For the sake of completeness, other things I gave a try before this were:
    – starting TB in safe mode (hold shift while opening thunderbird) and selecting those two checkboxes to reset stuff.
    – deleting global-messages-db.sqlite

Comments are closed.