After updating to Big Sur Mail.app automatically creates a replica of all my 4 account boxes under
the “On my mac” tab. It clutters the sidebar with at least 20 duplicate boxes I don’t want. I tried deleting them but I lose all the mails in the account. Plus as soon as a new email appears on an account the box is recreated "On my mac".
iMac 21.5″, macOS 10.13
In Mail Preferences, what is set for each in Mailbox Behaviors under the Accounts tab?
If set to the On My Mac folders, change them to the server folders.
Are they IMAP or POP accounts.
That's odd. I would remove the accounts and re-add them. I don't know what else to do.
Thanks Barney. They are all IMAP accounts. Only the iCloud account offers the option to keep emails on the server. For the other accounts the only option is to have them “on my Mac”. Does that mean it is a server problem? However it didn’t exist before the update to Big Sur 11.1. and it wasn't resolved with 11.2.
Thank you that worked!
Mail recreates inbox, sent, draft, junk and trash boxes “On my mac” tab.
