Restoring Lost or Deleted Mailbox

[Speed38]

I am trying to help a senior, via Zoom sessions, who contacted me because one of the mailboxes he set up in Apple's Mail.app, in [On My Mac] and not in iCloud, has gone missing.
He swears he did not delete it and I believe him because deletion of a mailbox is a multi-step process, and not likely to be done accidently.
He is running either Big Sur or Ventura on a two- or three-year old MB Pro.
He has a Time Machine backup.
Over a Zoom session, I went to ~/Library/Mail/ and found V10 folder, clicking on which produces multiple folders each with his own sub folders and I was afraid to proceed any farther for fear of buggering up his email.

Can anyone tell me whether or not is possible to go back a week and restore the entire V10 folder or some sub-folders in order to restore that lost mailbox?

Many thanks for any assistance.

 

[chown33]

Maybe he accidentally moved the lost mailbox, and it's hiding under some other mailbox. That's something that doesn't require multiple steps or confirmation.

If you can think of some msg content that was in the lost mailbox, you can do a search for it in Mail.app, also telling it to search all mailboxes. If it finds any msgs, then double-check it's really a "lost msg", then figure out where the mailbox is.


If it really is necessary to recover the mailbox from Time Machine, I'd try a test run first. To do that, create a new local Mac account, and run Mail.app from that account to try recovering the lost mailbox.

There may well be permission issues that prevent accessing a mailbox owned by Original User when accessed by TestUser, so it may not work.

There may also be temporary work-arounds that allow access to the TM backup, such as using Get Info in Finder to configure the external disk as "Ignore permissions". Here's an example thread discussing that option:

https://forums.macrumors.com/threads/external-hard-drive-permissions-have-changed-locking-me-out.2371009/

Found that by searching for keywords: ignore permissions

 

[orionquest]

If you are going to move it from TM, back up what is currently there first (to someplace else not time machine).
No need to make things worse.

 

[Speed38]

I am sorry to have troubled you fellow. I went back to the senior and, despite assurances on my part, he is literally terrified of making a mess of his email - which he once did on his own - and is going to go through the arduous process of recreating his missing mailbox and moving the appropriate emails to that new mailbox.

Again, sorry for the bother.