You could try right clicking on the Folder, select Properties and Repair the folder. Are you set up for an IMAP or POP3 account? Windows OS? The Trash folder could be manually removed in the folders and then it would regenerate but that would take a little careful work.

frisée, thank you for your response. I tried repairing the folder but that didn't seem to work. I have my settings to delete upon closing Thunderbird. I changed those to delete if older than 1 day, that didn't work. Then I changed them back. That didn't work either. Attached is a screenshot showing the imap account, and you can see all of the folders still in the Trash. It says that there are 0 messages in the yahoo account. I have logged into the yahoo account and there are no emails in the trash folder there. How would I manually remove the Trash folder in Thunderbird and regenerate?

Windows 11

How would I manually remove the Trash folder in Thunderbird and regenerate?

When Thunderbird is closed, go to C:\Users\[Users]\AppData\Roaming\Thunderbird\Profiles\XXXX.default-release then IMAP Mail. Then you would have to find the relevant IMAP account and navigate to the area where you have both 'Trash' and 'Trash.msf'. Move both folders into somewhere on your Desktop for safe-keeping. Restart TB and click on the root of the account.

OR, you could try this! Empty the TRASH! IMMEDIATELY do a Restart or shut down completely and then Boot up again. I had sticky FOLDERS trashed from a backup drive. I just finally did this emptying the TRASH and actually SHUT DOWN as it was late. When I powered up the next day the Trash was empty