You can not "just create" a trash folder.

Right click you account, select settings.

In server setting for the account select advanced. Turn off the option to only show subscribed folders. In "Imap server directory" place [Gmail} note the case is important

Restart Thunderbird to be sure the update takes place. you should notice a change in the folder pane which should include the replacement of the folder that were under your account with the ones that were in [Gmail] before hand. This is a replacement so you might loose sent mail if there is any n those folder you might want to copy it somewhere else for safe keeping.

Now go back to the server settings. Deletions should be set to trash on "Youremailaddress"

In the folder pane, the relevant trash folders should have a trash can icon. Do they?

Thank you for your advice.

I have done what you suggested, and still, when I delete an email from my gmail account, it's gone.

Deleted emails will not go to the trash folder.

When i followed your instructions, there was no trash folder nor trash icon. I added a sub-folder (see image) and deleted emails will not go there.

Every time I select a folder for trash in the settings, click OK, reboot TBird, the selection I made is gone, and the settings revert to "select a folder". Done this many times.

Thanks.

log into gmail in your web browser. In the settings there there is a setting labels. make sure all the folder you want to see in Thunderbird are selecting on the gmail web site.

That your setting does not stay selected is a worry however. As those are actually committed to file only when Thunderbird shuts down. it it possible it is not actually shutting down?

After you close Thunderbird press Alt+Ctrl+Delete and select task manager. If a little windows with show more details open select the more details.

In the processes tab is Thunderbird still listed?

What anti virus do you use? Recently McAfee in particular has been causing shutdown hangs in Thunderbird.

I had done some of what you have suggested already with no success.

Today, without any further effort on my part, deleted emails are tracking to the appropriate trash folder for all of my email accounts and the issue seems to be resolved.

It may be, as you suggest, that T'Bird wasn't shutting down all the way and finally did, don't know.

Thanks so much for your help in this regard.