Catalina Upgrade ruined my Mac Mail

AnaDenman79 wrote:

Hi, I've updated two Macbooks with the Catalina system and my Mac Mail has never been the same. Sometimes I have three emails in my Inbox, sometimes zero and others time 35. It's constantly downloading different amounts of emails. I've spent hours on the phone with Apple Support and they've decided that there's nothing they can do to help. PLEASE HELP ME! Thank you in advance, Ana

https://discussions.apple.com/content/attachment/795f9981-9134-4629-b60b-0932b9c20db0

For a single mailbox—You can rebuild a mailbox if it is isolated issue

Rebuild mailboxes in Mail on Mac - Apple Support

For problem accounts the go to way to sort things out is to delete the account, then add it back.

Remove email accounts in Mail on Mac

https://support.apple.com/en-lamr/guide/mail/mlhl9eb9408c/15.0/mac/12.0

Add email accounts in Mail on Mac - Apple Support

https://support.apple.com/en-lamr/guide/mail/mail35803/mac

Note—

• IMAP accounts stay on the server, so no local loss, when you re-sync

• POP accounts download and remove from the server—therefor save your inbox/sent box if you want them

• "On My Mac" is just that, local folders you created and moved mail into. So no loss

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