Mac Monterey mail takes forever starting

Hello ignazrc,

Thanks for using Apple Support Communities. You've done a great job trying to get this resolved. We recommend that you rebuild the mailboxes. This step can help with updating the list of messages in Mail.

Rebuild mailboxes in Mail on Mac - Apple Support

Let us know the results. Be sure to include specific error messages and additional steps that you may have tried.

Cheers!

Have you installed and run any "cleaning", "optimizing", "speed-up", anti-virus or VPN apps on your Mac?

Boot into the Recovery volume (boot with the Command + R keys held down  - Intel Macs) or  (How to Boot an M1 Mac into Recovery Mode), select Disk Utiity and run First Aid on all available volumes. Reboot normally and test Mail.

If that doesn't help I'd boot again into the Recovery volume and reinstall the system. This will not overwrite your user data but, as good practice dictates, it's wise to have a full and current backup before trying any installs.

ignazrc wrote:

Mac Book Pro M1, 2 users, first user mail works perfectly, second user spinning wheel for some 5 minutes (3 gmail accounts and one icloud account, around 30.000 mail messages)

Just installed Monterey, same behaviour

Tried to unlink all mail accounts (gmail and icloud) and restart "empty" mail, no change

Tried to delete relevant plist files and envelope files, no change

Tried to boot in safe mode, no change

at this point I have no better ideas, thanks for any help

Switch to 2nd User account, 2nd Mail account—

Quit Mail, relaunch the troubled Mail.app holding the Shift key down, and see if it sorts the issue. It is a bit of a Safe launch/safe boot.

Hey ignazrc,

Great! We look forward to hearing back with the results of that.

Cheers.