Preparing to move message 1 of 20

Thanks for replying, Raywood, and that additional info, it really helps! Next, use safe mode to start up your Mac as it does the following things:

• Verifies your startup disk and attempts to repair directory issues, if needed
• Loads only required kernel extensions
• Prevents Startup Items and Login Items from opening automatically
• Disables user-installed fonts
• Deletes font caches, kernel cache, and other system cache files

Log in to your user account and test the issue while in safe mode and then restart normally and test the issue again.

How to use safe mode on your Mac

Also, you mentioned you don't have this issue on your MacBook. What macOS version is installed on that Mac?

Have a great day and thanks for using the Apple Support Communities!

Hello Raywood,

Thanks for reaching out to Apple Support Communities. We see you have some questions about using the Mail application, and we'd like to help.

Have you tried force quitting Mail or restarting your Mac?

Are you using a POP account or an IMAP account with macOS Mail?

When you restart your Mac, does the issue remain?

Shut down or restart your Mac

Let us know, and we'll go from there.

Regards.