How do I find which emails failed to be copied?
I recently decided to switch from ProtonMail to Apple mail. I downloaded my email and loaded them into Apple mail locally. Thereafter I copied the local emails to iCloud and let the copying run over the night. Once the process finished I started to inspect the iCloud mailbox and found that there was two less emails in the iCloud mailbox than there was in the local mailbox.
How do I find which emails failed to be copied?