Mail on mac stuck 'moving messages'
I copied this from a 2020 posting that was made inactive. I was having basically the same problem, using Apple's Mail under Tahoe. I was able to resolve the issue, with information in that previous thread, which I'll post below, in case anyone is having the same issue. I do have an email account hosted by GoDaddy that uses Microsoft Exchange, which I think is the source of the issue.
"I use Mac Mail for emails, synced with an Exchange account. Ever since the Catalina upgrade, when I move an email from the inbox to other folders, or when I try to delete them, the Mail app gets stuck in 'moving messages' and so I would see the movement or deletion of the message locally, but it will not make the change in the server and the change will not sync to my other devices.
I tried restarting with no success. Also deleting the account from the app and adding it again. This did solve the issue for a day and then the problem returned.
This is a recurring issue. Please help."
MacBook Pro 16″, macOS 26.0