All Mail is just a label and all your Gmail has that label. It's best to not even show it in TB:

R. click account name above Inbox > Subscribe > untick All Mail.

I use 38 folders to organize my main email account (many as sub-folders), It happens that an email that I am looking for did not end up in the correct folder for some reason - drag/drop failure, etc. Without an all folders search, the "All Mail" folder allows me to find it. Also, including Trash in "All Mail" is a recent change in TB (this does not occur when using GMAIL via the web interface). Making the change you suggest eliminates a useful feature. "Search Messages" from the account is less "friendly".

Again, TB behavior has changed by including items that are in the "Trash" folder in the "All Mail" folder and should be returned to the way that it previously worked to not include "Trash" folder entries.

All Mail is just a label and all your Gmail has that label. It's best to not even show it in TB: R. click account name above Inbox > Subscribe > untick All Mail.

Actually, "All Mail" is not a label, it is the repository for every gmail message. Everything else that you see presented to you in Thunderbird (and in gmail) is a gmail label, including Inbox. gmail's imap presents these labels as imap folders, which in Thunderbird you can subscribe or unsubscribe. See https://support.mozilla.org/en-US/kb/thunderbird-and-gmail#w_gmails-particularities

But you are correct that "All Mail" imap folder in thunderbird is not needed.

After deleting an email (GMAIL) from any folder and emptying Trash, the email is still in "All Mail". Deleting from "All Mail" and emptying Trash still leaves the email in "All Mail" - in fact, selecting the email to be deleted in "All Mail" and then selecting "Delete" causes them to disappear and then reappear. This used to work correctly. Using !39.0.1 64 bit version. Note: I recently had to reinstall Thunderbird after a systems issue - causing me to reinstall Windows 11 and noticed the problem after that. It might be that the GMAIL "Trash" folder has been linked to "All Mail". I can delete the emails by signing on to GMAIL on the web and deleting them that way.

So you are saying, in version 128 trashed messages did not appear in the All Mail folder, but in 139 they do appear.

But my understanding is every message should appear in the All Mail folder, even if it has the trash label, and even after trash is emptied. The only way to get a message out of All Mail is to literally delete it while in the All Mail folder.

However, I have seen people report varying results.

In the earlier version (not certain which level) and for all previous versions going back many, many years, items in the "Trash" folder were not included in the "All Mail" folder in TB. This is also the case using the web interface for GMAIL - that is, items in "Trash" are not added to "All Mail". The problem is that when "Trash" items are included in "All Mail", that you can never delete them, because as soon as they are "Trashed", they reappear in "All Mail" and emptying the "Trash" only clears them out of the "Trash" folder, but they remain in "All Mail". The only way to get rid of items is to use the GMAIL web interface or eliminate the "All Mail" folder in TB.

Though you and others may not find the "All Mail" folder necessary, that is subjective.

Note: there have been times in the past that Deleting an item from a folder (label), did not always delete the item from "All Mail", but I was able to delete them from "All Mail" and they did not reappear in "All Mail". Again, the current behavior results in items staying in "All Mail" forever regardless of the method of cleanup used within TB (excluding using the GMAIL Web interface).

Just a side comment: I avoid AllMail because it doubles your disk space and doubles your network use and doubles your computer resource use. Eveything you do is done twice.

David, I appreciate your perspective. That said, I only have in the vicinity of 40 emails a day across 3 GMAIL accounts that I track with TB. My 500GB SSD Windows System drive is only using 70GB (which is used by TB) and my 2TB Data drive is not impacted. Further, I set up "Retention Policies" for most of my folders to help manage the age of emails that I keep. In addition, my internet provider is ALLO and uses fiber with 500 Mbps both upload and download. Thus, your concern is less of an issue for me.

Further, since "All Mail" is a standard folder that TB sets up for accounts, it seems to me that it should work correctly and not create a situation where emails cannot be fully deleted using only TB.

Ed said

All Mail is just a label and all your Gmail has that label. It's best to not even show it in TB: R. click account name above Inbox > Subscribe > untick All Mail.

Actually, "All Mail" is not a label, it is the repository for every gmail message. Everything else that you see presented to you in Thunderbird (and in gmail) is a gmail label, including Inbox. gmail's imap presents these labels as imap folders, which in Thunderbird you can subscribe or unsubscribe. See https://support.mozilla.org/en-US/kb/thunderbird-and-gmail#w_gmails-particularities

But you are correct that "All Mail" imap folder in thunderbird is not needed.

All Mail is also a System label.