User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:106.0) Gecko/20100101 Firefox/106.0

Steps to reproduce:

After updates on an Lubuntu 22.04 version 5.15.0-52-generic including an update of Thunderbird to version 102.4.2 (64-bit) I needed to restart my machine.
After the restart starting Thunderbird lost all folders of my email account except for "Inbox" and "Trash".

Actual results:

Thunderbird deleted folders and its content and keeps doing so after exiting and restarting.

After the restart of my machine and the update to Thunderbird 102.4.2 all folders including its content of my (IMAP outlook.office365.com) email account except for "Inbox" and "Trash" were deleted.

When I create a new email and then press "Save" it tries to copy the email to "Drafts" (which never finishes, the copy dialog does not finish). This recreates a new folder called "Drafts" in my account on the local storage and when clicking on it, Thunderbird downloads the full content from my mail account.
Similar to when I press the "Send" button and the "Sent" folder. (The email is also actually sent but not copied to the "Sent" folder.)

Exiting Thunderbird and restarting it, the "Draft" and "Sent" folders and its content are deleted again.

I also tried a local (non-system) Thunderbird installation, also 102.4.2, (using a different profile) which behaves the same.

Expected results:

The folder and its content should be kept and in sync with the IMAP account.

I downgraded to a 102.1.2 but the bug persists and and did not fix the behavior.

Hello micwinx, sorry for those hassles!

• I understand that only your folders in Thunderbird have disappeared from the UI, but the actual messages are still available if you access them via Web interface of your email provider, correct?
• Are your Thunderbird accounts set to use OAuth? Now required:
  https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-online

This sounds like bug 1798685.

I understand that only your folders in Thunderbird have disappeared from the UI, but the actual messages are still available if you access them via Web interface of your email provider, correct?

Yes, this is correct, the messages are still accessible via the Web interface of, in this case, outlook. Also, on another machine (I do not know the thunderbird version there) I still have all folders and it's content.

Are your Thunderbird accounts set to use OAuth? Now required:
https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-online

Sadly, I recently also noticed that one time AppPasswords are not working anymore and I had to switch to OAuth, so yes this is used right now.

One additional comment of what I found out and might be related to this bug is that on the "Subscribe" option on folders of my mail account checking the checkboxes is not saved and has no effect (e.g., clicking the checkbox for the "Sent" button and either then "Subscribe" or "Refresh" is not saved (the latter just clears the checkbox directly, the former has no effect)).

P.S. I will take a look at https://bugzilla.mozilla.org/show_bug.cgi?id=1798685 , thank you for pointing this out.

Since I cannot comment on https://bugzilla.mozilla.org/show_bug.cgi?id=1798685, does anybody have a bug report link on Microsofts website regarding this issue (I and probably others would find this helpful)? @Piotr Koper, I explicitly mention you here since you ran into this and determined it was a Microsoft issue.

I have installed Outlook desktop client "Microsoft® Outlook® for Microsoft 365 MSO (Version 2209 Build 16.0.15629.20196) 32-bit " and the bug is not visible, which means Outlook itself works well and all folders exist and are accessible.
So this is unlike what @Piotr Koper was saying in the item which marked this one here as duplicate.

This brings me back to that this is a thunderbird bug very likely caused by some changes from Microsoft that suddenly created some incompatability.

Any help is appreciated. Please reopen this item.

Best regards,
Michael

@Magnus Melin, could you please reopen this issue. As described above, all email folder exists within the Outlook Desktop Client, so the bug exists only within thunderbird, maybe other email programs.

This bug is duplicate of bug 1798685, so discussions would continue in that bug. This is closed.

Anyway, whatever is going on there's only been a few reports so difficult for anyone to pinpoint the issue (which I'd still maintain is highly likely a server side bug).
You could try to get imap logs - https://wiki.mozilla.org/MailNews:Logging
Try with current and older releases of Thunderbird. If it works with an older release and not with a newer, Thunderbird could be at fault.
http://ftp.mozilla.org/pub/thunderbird/releases/. You can start older releases by specifying -allow-downgrade. Backup your profile.