What are you trying to achieve in the first place?

Hi. Trying to close TB and reopen with same tabs. Not just Inbox and Calendar. Thanks.

If you delete those files then the tabs will disappear when you start Thunderbird. That is expected. The reason for deleting those files is to resolve an issue which may have occurred due to a corrupt file.

Are you still discussing the problem where you have opened tabs and lost data in the tab header? The question you started in this location ? https://support.mozilla.org/en-US/questions/1344828

If yes: What version of Thunderbird are you currently using? What (if any) addon extensions have you installed whether theya re enabled or disabled - post an image as it might be quicker.

Previously you said "Tab is blank and email disappears." Can you eleborate on that... Does only the email content in tab disappear? In other words email itself still exists in the folders and you can easily reopen and read?

Did you do this: open selected email in tab and leave it to view later Then did you move the email to another folder perhaps for organising? Are you talking about a email which is in an Imap mail account ? If you moved email - did you move it to another imap folder or into 'Local Folders' mail account?

Are you using View > Folders > Unified or All? When you opened the email to view in tab, did you select email which was in a Unified Inbox folder or the account Inbox folder?