In the TB profile folder, messages are stored in mbox files - one file, with no extension, which contains all the messages in a folder - and an .msf file with the same name that is an index of the folder. Tags are stored in the .msf file. If the .msf file was corrupted, it's possible that causes what you're seeing - tags not being retained. You can delete the .msf file (while TB is closed), and it will be automatically recreated when TB is restarted. Or, right-click the folder in TB, Properties, click Repair Folder to rebuild the index. See if that corrects the tag problem. Note that repairing the folder will force a re-download of the IMAP folder.

Thanks for your hint, I tried it but it did not fix the issue. I also updated TB to 68.2.2

Any other idea?

Same problem here, lost ability to tag emails after upgrading to 68.2.1. Upgraded again to 68.2.2 hoping it would fix problem and it did not. Clearly TB has a bug in their recent upgrades. This isn't the first time an upgrade has resulted in lost tags.

Are these lost tags ones that belong to the built-in set, or user-created tags? Note that if the IMAP server doesn't support IMAP keywords, tags are stored only in the .msf file, so that if the folder is repaired (or the msf file is deleted), the folder is re-downloaded, and the tags will disappear. The question here is if, after a folder repair, tags are retained on the local computer, irrespective of whether the server stores them as well.

I don't notice any issues here with tags, so it's too soon to declare a bug. It's more likely an issue with a particular folder's properties or the IMAP server.

Try running TB in safe mode and retest, in case there is an add-on or layout problem. Hold Shift (Mac:Option) when you launch TB.

Ran TB in safe mode on MAC as suggested. Tagged a few emails, but again after leaving inbox and then returning the tags had vanished.

Should be noted this problem is only happening with my Inbox emails and it's only when I try to tag emails dated 10/25/19 or later. The older emails are holding their tags.

The emails in my Sent folder are holding tags - new and old.

pamela6 said

Ran TB in safe mode on MAC as suggested. Tagged a few emails, but again after leaving inbox and then returning the tags had vanished. Should be noted this problem is only happening with my Inbox emails and it's only when I try to tag emails dated 10/25/19 or later. The older emails are holding their tags. The emails in my Sent folder are holding tags - new and old.

Did you try repairing the folder or deleting the msf file, as above? You will lose the tags if they aren't supported by the IMAP server. If that doesn't help, I would rebuild the Inbox folder; it is the folder most susceptible to corruption.

To guard against tags being lost, I usually build them into a message filter that can be run manually when necessary.

sfhowes said

Are these lost tags ones that belong to the built-in set, or user-created tags?

buil-in set

Note that if the IMAP server doesn't support IMAP keywords, tags are stored only in the .msf file, so that if the folder is repaired (or the msf file is deleted), the folder is re-downloaded, and the tags will disappear. The question here is if, after a folder repair, tags are retained on the local computer, irrespective of whether the server stores them as well.

I do not know if my IMAP server supports IMAP keywords, anyway I experienced this issue after updating TB to 68.x.x. As you suggested I tried to repair inbox folder but this not fixed the issue.

I don't notice any issues here with tags, so it's too soon to declare a bug. It's more likely an issue with a particular folder's properties or the IMAP server.

I'm experiencing this issue in all folders, not only in inbox.

Try running TB in safe mode and retest, in case there is an add-on or layout problem. Hold Shift (Mac:Option) when you launch TB.

Done, but same problem.

B-)