I switched my mail from POP to IMAP last night and it wiped out my inbox of anything before December 14. When I enter time machine, I cannot find a V9 folder from prior to last night, let alone the library folder so that I can get to the mail folder.
MacBook Pro 14″, macOS 12.6
In a Finder window, go to your "home" folder (the one with your username, it has a house icon).
Open the View menu and in Show View Options check the box to show the Library folder.
If you still don't see the Library folder inside your user home folder, go to your user home folder and hold the Option key while clicking on the Go menu, and go to the Library folder there.
In the Library folder, open the Mail folder. You should see a V9 folder, just leave that Mail folder open with that V9 folder showing.
Now enter Time Machine, it should open to show the folders inside that Library/Mail folder, including the V9 folder. You can restore an older V9 folder from an older backup. In case something goes wrong, keep a copy of the current V9 folder (you can make a backup copy of it somewhere else on your computer, or Time Machine may ask you if you want to keep both (the current and the V9 folder from the past being restored).
Since I have my Library visible, I can't recreate your situation exactly.
First, when viewing contents of a Time Machine backup directly, never make changes to it but it is ok to copy from it.
Try this:
In the Finder, go to the backup on the TM disk you wish to view, choose one from before Dec. 14 when you wiped out your emails. Select your Home Folder in the user folder of that backup. Right click on your account name (control click) and then hold down the Option Key. Select copy "***" as pathname.
Then, go the the Finder, select Go from the menu, then Go To Folder and paste the above copied pathname to the window. Add (type) /Library to the end of the pathname in the window, then hit Go. A Finder window show open that backup user Library folder. Then you can open the Mail folder and look for the V9 folder. If this is from before Dec. 14, you can try copying it into your current user Library on your computer -- to replace your current V9 folder with that backed up V9 from within a Time Machine backup earlier than Dec. 14.
Before doing this, in case it does not work, rename the current V9 folder (on your computer) to V9_old in case you need to bring it back.
Thanks for this - yesterday this approach was successful whereas when I first tried it and pasted the address into the "go to folder" pop-up, it wouldn't allow me to go to the folder.
My mail has been retrieved - thanks all for the suggestions.
When I do this and enter time machine, it will only show me the latest V9 folder. Library, and subsequently Mail, are not visible in the older folders.
recovering mail from Time Machine with Monterey
