Steps to reproduce:

• Start Thunderbird and fetch mail
• Try to Archive an email by using the 'a' shortcut or by clicking the 'Archive' button.

Actual results:

An error shows (see attachment) saying "The operation failed because another operation is using the folder. Please wait for that operation to finish and then try again.

Things I've Tried:

• Disabled all plug-ins.
• Compacting mailbox and affected folders

Expected results:

The email should have been archived.

I should also state that this is sporadic (It only happens on occasion - not consistently).
I've also attached a screenshot of the debug console when the error happens.

POP3 or IMAP account?

POP3

Thanks! I had no issues on my first archiving attempt of messages in my POP3 account using 98.0b2 on Windows 10, or Fedora 35 Linux.

I guess I'll have to try sporadically.

It's quite sporadic and seems to have only gotten worse recently. Initially when I started having this happen a few weeks back, the compact or the "Repair Folder" options seemed to help, but that could have just been a coincidence too.
Perhaps it has something to do with the number of emails in my mailbox (approx 140k)

(In reply to Meichthys from comment #6)

It's quite sporadic and seems to have only gotten worse recently. Initially when I started having this happen a few weeks back

Is that December 2021? Or January 2022?

Perhaps it has something to do with the number of emails in my mailbox (approx 140k)

I that the Archive size? If if so, what is the Inbox size?
Can this be reproduced with Windows started in safe mode?

Do you have imap accounts for which this does not happen?

There are other examples, none of which come to satisfactory conclusion (except those involving anti-virus): Bug 503954 - Archive multiple messages and more https://mzl.la/3pHeSpV

That is the Inbox size (Although my archive is a subfolder under the inbox and I generally use the 'zero inbox' method of reading emails (All emails get moved to the archive folder after i'm done reading/interacting with them).

I do not have any imap accounts unfortunately.
I haven't tested in SafeMode yet, but will try when i have time.

This morning when it happened, i noticed a flash in the bottom status bar that said (Compacting complete). After that flashed, I could archive again.

There is a loading bar which i hadn't noticed in the past that indicates that the mailbox is compacting.

My current compact setting is set to only compact when it will save more than 50MB. I doubt that it is saving 50MB each time it is compacting for me since sometimes there is no change to my mailbox when this issue happens.

For now I've enabled the "Ask every time before compacting" option to see if the issue only happens immediately after approving the compact task.

After making the above change and subsequently changing the MB cutoff to 1000, I haven't had this issue.

We can probably mark this issue as resolved, but It does still seem strange to me that it would have tried to compact so often even when I had very little (if any) changes to my mailbox.

To follow up here, After not seeing this issue for almost a month, I'm now seeing this issue again every 15 minutes or so (even with the MB cutoff set to 1,000).

To me it seems like the compact process isn't actually working. When it prompts me to compact it indicates that about 500MB will be saved. After clicking "Compact Now" it seems to finish normally, but then prompts to compact again every 15 minutes or so.

Perhaps related to Bug 1757181

I was able to verify that the compact is not doing what it says.
The size of my profile folder changed by less than 200KB after the compact was complete and Thunderbird showed "Done compacting (approx. 507 MB saved)".

(In reply to Meichthys from comment #13)

Perhaps related to Bug 1757181

You cited this bug, but you must mean a different bug report - from https://mzl.la/3pHeSpV ?

Or perhaps bug 837620? (from this expanded search https://mzl.la/3DndSya)

I'm honestly not sure what i was trying to reference, but I haven't seen this issue in v106, but it might be because I have migrated to maildir.

Thanks for the update. Please add new comments if the problem should reappear.