Stuck: iMac Big Sur Mail recovering 695,000 messages
I just upgraded my wife's iMac 2017, plenty of hard drive space, 8MB RAM, to Big Sur, and used Migration Assistant to bring in data & settingsj after an internet recovery, in which Apple Hardware Test found no problems.
When she opened Mail, there was a long (hours) period of "preparing to import messages." This was followed by a long (days) period of "importing recovered messages." It froze at 61,000 of the 695,000.
Reboot did not help, except that when I attempted to open Mail again, the very large number of messages seems to be coming from a different mailbox: [Gmail]/Drafts.
This process now also seems to be hung. Any suggestions?
She tells me she "spent days" deleting email messages a few months ago. Her work habits often shock and amaze people who become aware of them, so the range of possible explanations for what is going on is very large indeed.
iMac 21.5″, macOS 10.14