This puzzles me, as I am not sure of your request. Compacting can be fully controlled manually, so I'm curious why you just don't disable automatic compacting and do periodically as you see best while cleaning out your folders. I think I am missing something, but don't know what. :)

David: I found a Disk Space setting that refers to compacting when x MB of disk can be saved. Is this what you're referring to when you say I can "fully control" manual compacting? I unchecked the box and re-started Thunderbird, but the empty trash/compact folders requests keep coming, albeit a little less frequently. Let me be clear: the requests are coming from Thunderbird and say I can't delete any more e-mails unless I empty trash and compact a folder (or folders).

Would you please post a screenshot of that message?

Rick (see attached for the image). I created a file to give you more detail associated with the problem, but your system wouldn't let me attach it (VERY frustrating given the time I've spent putting it together for you). I tried replying to the e-mail address you used to send your request for an image, but it said that address was not monitored. I "replied anyway" hoping the document will get to you. If it doesn't get to you, please send me a more private e-mail so I can get it to you.

We are all users of Thunderbird supporting each other here. This is not my system. The e-mail message that you received was just a notice that I had responded to you in this forum. All communication happens here, not through e-mail. I'm sorry about your frustration.

You shared your screenshot successfully. Thank you.

That problem is often caused by anti-virus software and the solution is usually to create an exception or exclusion for your Thunderbird profile in the anti-virus software settings. If you search this forum, you will find more information.

My antivirus does exception-ing by individual files. Please let me know which files within the Thunderbird Profiles folder I should be exception-ing. I am using Windows 11.

I do not use Windows or anti-virus software. All I know is what I have read on this forum, which I have already shared. Sorry. Other people have provided detailed answers on this forum. Good luck.

You might try running in troubleshoot mode and checking the error log. That may provide some useful info for you.

There is currently a bug or two that causes this issue. AV so far is not implicated, and Troubleshoot Mode is not known to help either.

For now, disable automatic compact and/or set a higher threshold value.

Thanks, Wayne.

Wayne, thanks for responding. This is the first indication I've had that the Thunderbird development team knows they have a problem with managing disk space. I just wish they'd focus more on nuts and bolts infrastructure issues like this one instead of expending so much effort coming up with new features that I don't really use. I'll slog on with my e-mail deletion process and put up with these annoying empty trash/compact folders requests. By the way, I have disabled automatic compacting and made exceptions of index and index.log in my antivirus program (both to no effect on the problem). I did discover some compacting options in Settings/Indexing/Config Editor/Show All, but I don't know enough to be messing around with any of those.

I failed to mention, this is not a disk or disk space issue. In fact the error message generated, in this case, does not correctly indicate actions that would be useful to a user.

There is nothing you should do in config editor.

p.s. you might be able avoid some extra work/overhead/time in the future when doing big cleanups, if you are being careful about what messages you have chosen to delete, by using shift+delete to do immediate deletions. Immediate delete skips putting messages in the trash folder.

Regardless of your methods, one should still seek to keep the trash folder lean. Eventually, later, you will still want to do "Compact Folders".

Wayne, thanks for responding --- again. You are correct. I shouldn't be speculating that this is a disk space management problem, but it is a bug in the software. "Empty trash" and "Compact folders" suggestions in order to keep the software functioning should not be required. In fact for years (before the "new generation" of Thunderbird software) I intentionally chose to ignore Thunderbird compact folder suggestions and had no problems. It's only with the most recent releases that I was forced to compact messages in order to keep the software functioning. This problem needs to be fixed. Finally I'll say that compacting IS a credible suggestion for the software to make, but only to save disk space for users where disk space might be an issue, not as a requirement for keep the software functioning. Oh, and I don't like using the the "forced delete" mechanism you suggest because I occasionally refer back to a message in trash I shouldn't have deleted, which leads me to another product improvement suggestion. Thunderbird does a good job of managing the Junk folder, automatically deleting old messages in the Junk folder. There should be an option in Settings to allow users to do that with the Trash folder. If that were available, I would set it at 3 (or 6) months (ask the software to delete Trash messages older than 3 (or 6) months).

Well, you weren't speculating - the error message specifically called out disk space. I'm merely clarifying that in the case it's likely not a factor.

Suggestions for product improvement are taken at https://connect.mozilla.org/t5/ideas/idb-p/ideas/label-name/thunderbird

Wayne, Thanks for the link --- much appreciated. I want to be more specific about something. When I use the phrase "software not functioning properly" I mean that as I delete messages the software eventually gets to the point where I cannot delete any more messages without emptying trash and/or compacting a folder (*). Emptying trash and/or compacting folders should not be a requirement for the ability to delete messages. I would think that emptying trash and/or compacting folders should only be a suggestion for SAVING disk space. Not sure about this part: I would think the operating system itself would warn me when I am RUNNING OUT of disk space. I wouldn't think that notification should be Thunderbird's responsibility.

(*) When this happens (having to empty trash and compact a folder) seems to be random. Sometimes I can (cumulatively) delete over 200 messages (using multiple deletes) without having to empty trash and compact a folder. Other times, I can only delete 25 (one page of) messages and I get the error message (and have to empty trash and compact a folder). I try to watch (and make mental note of) the space saved while compacting a folder during this process. It ranges from sometimes as small as kilobytes to up to 30MB (very variable). Sometimes exiting and re-starting the application seems to help. Just wanted to give more insight into what's happening.

Sorry, it seems I have confused your issue with something else that is going on. But I'm thinking more clearly now ...

I'm checking into some possibilities. While I'm doing that: 1. Your Thunderbird profile (data) is entirely on one disk drive? 2. What is the size of that drive, and how much space is shown to be free? 3. Start Windows in safe mode with networking enabled - https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode. Does problem change?

Real quick because I'm buried with e-mail goals. I'm forcing myself to go through 1,400 e-mails per day (deciding which e-mails I want to save on my hard disk before I delete them and which e-mails I just want to delete). I'm moving to a new computer and have vowed NOT to take these old e-mails with me and I WILL get this done by 6/22. Yes, I believe my Thunderbird profile is on one disk drive (I only have one disk (C) drive). The size of the drive is 1TB and I have 617GB free. 1) Starting Windows in Safe Mode will be delayed unless I get ahead on my e-mail goals. 2) I don't think the Compact Automatically setting is a factor (at least not for me). I had it set (before I turned it off) at "Compact all folders when it will save over 500MB." It's asking me to compact (box checked or not) well below 500MB. 3) I think the number of messages/e-mails out there is a factor. I just finished the Inbox for today (deleting 718 messages). When I started (on 6/8) I had 11,593 e-mails in my Inbox. After today I will have 4,100 (approximately). As I reduce (delete) the number of e-mails, Thunderbird's tolerance (for allowing me to delete e-mails without requiring me to empty trash or compact a folder) seems to grow. When I finished today I had 443 e-mails in Trash to empty (a record since I started) and the compacting saved 164MB (also a record).

As you suggested, I re-booted in Safe Mode tonight and the problem went away. At the end of my analysis of my Sent folder, I was able to delete 539 e-mails from my Sent folder using one click on the Delete button without getting the message asking me to empty trash and compact folders. I now have 556 e-mails in Trash. I will continue in Safe Mode tomorrow without deleting any of the e-mails from Trash. I noticed I was not able to get to the internet while in Safe Mode, but I am not concerned about that since my focus is on getting through (and deleting) my e-mails in preparation for moving to a new computer, and I rarely need to interact with the internet to do that, although some e-mails do contain web links I would like to get to, but I can defer analyzing those until I get back into normal boot mode. I will keep you informed as I move forward.

Good info.

Which Antivirus (or similar) software do you use?