One of the most useful features in macOS is Time Machine, the built-in backup software. If you have an external or network drive, Time Machine backs up your Mac every hour, and retains hourly backups for 24 hours, daily backups for the past month, and weekly backups beyond that. It’s simple to set up, and requires no user intervention. And it’s great, when it works.
Since the release of macOS Catalina, Time Machine doesn’t work with Apple Mail. If you enter Time Machine from Apple Mail, you are supposed to be able to see your email in all your backups. But if you try to do this is Catalina, Mail crashes.
Looking at a crash log, I see this:
Error Domain=NSCocoaErrorDomain Code=256 "The file “Accounts.73319.db.timemachine” couldn’t be opened." UserInfo={NSFilePath=/var/folders/9r/009mv58n4x172dtpkp5nrctc0000gn/T/com.apple.mail/Accounts.73319.db.timemachine, NSSQLiteErrorDomain=14}
This looks like it might be a permissions error, or something to do with the way users access system files in Catalina.
This has been a problem for months, and users have reported it and filed bugs about it. It only hit me the other day, when I needed to find an email I had accidentally deleted (or that Mail had deleted without my intervention; that’s another story…)