A friend using MacOS 12.7.1 is having problems with Mail. Mail works quite well as long as they don't activate their IMAP account; they have some local mailboxes from an old POP account. Connecting and trying to synchronize with their one IMAP account causes Mail to increase its memory usage (in Activity Monitor) until it's about 15 GB, and the system notifies the user that they're out of application memory. The system has 16 GB of RAM.
Connecting to the same IMAP account with Thunderbird proceeded without any problems for the user.
I also set up a brand new user account and then used Monterey Mail to access the same IMAP account. While synchronizing, total memory usage for Mail was roughly 100 MB and stable.
So I think I eliminated the account's IMAP server, and macOS Monterey Mail for a different user. But now I'm trying to find reliable information on how to deal with whatever may be wrong with their preferences/indexes/caches etc etc. I'd like to reset to "factory stock". I have no problems with exporting their local mail boxes to .mbox if necessary. I don't want to lose messages. I've found quite a few guides that unfortunately are considerably older than Monterey
Connecting to the same IMAP account with Thunderbird proceeded without any problems for the user.
I also set up a brand new user account and then used Monterey Mail to access the same IMAP account. While synchronizing, total memory usage for Mail was roughly 100 MB and stable.
So I think I eliminated the account's IMAP server, and macOS Monterey Mail for a different user. But now I'm trying to find reliable information on how to deal with whatever may be wrong with their preferences/indexes/caches etc etc. I'd like to reset to "factory stock". I have no problems with exporting their local mail boxes to .mbox if necessary. I don't want to lose messages. I've found quite a few guides that unfortunately are considerably older than Monterey