The 'Trash' folder is for unwanted emails that you do not need. The 'Trash' folder stores emails that you selected to delete. The 'Trash' folder is used to receive deleted unwanted emails, so if you delete in error then you can recover them and return them to another folder. So it is a catch deleted emails folder just in case you delete in error.

Do not put emails that you want to keep in the 'Trash' folder. It is not designed to store emails that you do not want to delete.

Move those emails out of the 'Trash' folder and put them into a much better folder that serves the purpose you require, even if you have to create a new folder called 'TempHold'.

If you need to store older emails on an ongoing basis for historical record then use the 'Archive' option.

Warning, if you use an imap account then many servers will auto empty the Trash periodically. Gmail is an example of a server that does this.

Please only delete emails that you want to delete and empty the Trash periodically.

I agree and have been doing as suggested with Archives. I try to keep current, but sometimes lag behind and then I loose mail that became relevant. If one accidently clicks on the wrong button of that constant pop-up then all is lost. please stop with the popup request. It is really hard to be current with Archives.

re :please stop with the popup request.

I'm wondering if you are getting a pop up that is asking to 'compact' folders and not empty the Trash, because it is really odd to be asked to empty the trash.

When you delete or move a message to another folder, then that message will appear in either the TRash or other folder eg: Archives, BUT that message in the original folder is marked as deleted and hidden from view, it is there taking up space and making the original file rather messy. That file needs to be cleaned up to help prevent it from becoming corrupted.

Please Read this about compacting because it is important. https://support.mozilla.org/en-US/kb/compacting-folders

I compact all the time. The little popup box reads "the messages you have deleted can be purged from disk. Select the option to let TB do this automatically"; then a check box and 2 selections, "proceed" & "cancel". If I select proceed my trash is permanently lost. It would be nice to opt not to receive this request in the future. The point is that it is really hard to know what is temporary trash and permanent trash until much time has passed. I wish TB would stop trying to do my work. Not user friendly. Thanks, Steve

Please test the following: In version 68*: Menu app icon > Options > Options > Advanced > 'Disk Space' tab

In Version 78*: Menu app icon > Options > General Scroll down to 'Network & Disc Space' section under 'Disk Space'

Do you have this selected: 'compact all folders when it will save over xxmb' ? If yes, uncheck that option restart Thunderbird.

Please report back on results.

I'm currently trying to find some info on why Trash is being deleted when you expect only a compact of all folders.

I have changed the settings as you suggested on both the tablet and PC. There are no more messages. Thank you for your help. Steve

stwmrs Did the problem occur in an Imap or POP account?

Some servers do auto empty the 'Trash' periodically. Some do it once every 30 days and some do it once every two weeks. So if you have an Imap mail account then it could be the ettings on the server emptying that Trash folder.

Just for clarity, can you confirm whether this was a POP or IMAP account ? I'm trying to check for any weirdness occuring with that pop up which should not be happening. Your feedback would be much appreciated.

I have IMAP. In Server settings; Message storage, the empty trash box is UN checked. Thanks, Steve

I have been struggling with the same annoying popup, and thank you for all the help.

I have an IMAP account, and I would be delighted to have Thunderbird automatically COMPACT my folders. For now I have set the compacting setting to a larger size, but if this setting is for deletion reminders and not for compacting folders, something needs to be fixed!

I use retention policies to manage my emails, and to permanently delete Trash, and do not want extra help reminders!

I have been struggling with the same annoying popup, and thank you for all the help. I have an IMAP account, and I would be delighted to have Thunderbird automatically COMPACT my folders. For now I have set the compacting setting to a larger size, but if this setting is for deletion reminders and not for compacting folders, something needs to be fixed! I use retention policies to manage my emails, and to permanently delete Trash, and do not want extra help reminders!

It is to remind you that the threshold you set for compacting folders has been reached and you should compact folders. Just because you delete emails with retention policies does not mean the hidden marked as deleted emails have actually been removed. That's why you need to compact the folders. It's basic housekeeping maintenance to ensure folders stay in a healthy condition. When you delete or move emails, the email appears in a different folder eg: Trash, but the original emails in the original folder is still there. It is hidden and marked as deleted. Once the amount of space being occupied by those hidden and marked as deleted emails reaches the threshold you have set and you have not been manually compacting folders, then the reminder pops up. You can set imap Inbox to automatically compact (purge) when you exit Thunderbird. Account Settings > Server Settings under 'Message Storage' select : Clean up (Expunge) Inbox on Exit.

Personally, I manually compact Inbox, Drafts and Junk/Spam each day as they tend to have the most deletions/moves. I do not set a high threshold because I want my files to stay as healthy as possible as this reduces the risks of corruption.

Perhaps it is a matter of poor wording and confusing messages:

1) the so annoying popup message does not say anything about compacting folders, but about permanently deleting emails. Since this appears when I move or delete a new message from my Inbox, the implication and concern is that it may permanently delete this and other newer messages (there is no reference to any folder retention policies, etc.).

2) the setting in options implies that Thunderbird will actually automatically compact folders, not just display a message about permanently deleting messages! The wording is "Compact all folders when it will save ___ MB in total".

I have my Trash folder retention policy set to delete messages over a set number of days old. I assume that this is indeed a permanent deletion, as email do disappear from the Trash folder.

Is this not the case?

re :Perhaps it is a matter of poor wording and confusing messages: Totally agree with you.

Yes the wording is a pain and I've been fighting for months to get it sorted. Have a look at this bug report and you will understand I'm not on own, but I'm not getting any real support from the developers. https://bugzilla.mozilla.org/show_bug.cgi?id=1678856

re :Since this appears when I move or delete a new message from my Inbox, the implication and concern is that it may permanently delete this

You either have moved the emails into a different folder or selected to delete it in which case it is now in Trash. So yes, you have now got a 'hidden' trace left in the Inbox of the 'deleted/moved' email and it is that 'hidden trace'; that original copy; that needs to be cleaned up - removed - deleted and the process to do this is called 'compacting'. It tidies the file because you do not want it to keep hidden copies of marked as deleted emails that bloat the file.

It does not mean to delete the email in the folder that is was moved into; that moved and 'visible' copy would still be in whatever folder it was moved into.

It has nothing to do with the 'Trash' folder.

Compacting information: https://support.mozilla.org/en-US/kb/compacting-folders

Thank you for your patience in continuing to explain. I still feel a bit fuzzy about what is happening, but perhaps I get the gist...

The information in the link you provide about compaction states very clearly that Thunderbird will automatically compact folders based on the disk space threshold.

It does not say that it will popup a confusing message about deleting messages...!

The average user should not have to understand the underlying mechanisms for deletion and compacting, and any popups requesting confirmation for actions that cannot be undone should be very clear.

This seems to require some re-design!