I just migrated from my M1 iMac on OS 26 to a new M6 iMac with OS 27.2. I brought my files over with a Time Machine backup, which mostly worked. However, when I opened Mail, I got a message that the emails had to be imported into a new version of Mail. I had over 10,000 emails but only 324 were imported.
Now what? I don't want to lose the old emails.