Mail unresponsive when opening preferences

Old Toad wrote:

At this point I'd Boot into the Recovery volume (boot with the Command + R keys held down), select Disk Utility and run First Aid on all volumes. If that doesn't help I'd boot again in the the Recovery volume and reinstall the system.

Because this is a quite new computer, and applications were installed fresh rather than migrated, I doubt that reinstalling the system will help. Because the problem is only a several minutes delay in response, rather than a true system crash, it is not currently worth that step.

I can confirm, however, that running just first aid in recovery mode did not find any problems I did not fix the slow opening of mail preferences.

And while the musings on VPNs are very interesting, especially in light of all of the articles that recommend VPNs for nearly everybody all the time (!), the question of VPN is not relevant for this issue at this time, because I am not running a VPN at all. I used to run a campus-specific VPN only for access to the work campus, and I had previously assumed something about that VPN, or the security software they required in order for me to have access to it, was the cause of the slow down with Mail. This new machine does not have that account set up, nor have that security software installed, nor that VPN.

Took it to Apple advisors and no joy after resetting SMC; test user with one account enabled did not do it; disabling all but one account did not do it in my own account.

I uploaded a screen recording and a log to Apple and may hear back sometime next week.

The answer that was selected solved above was incorrect, and There is no way to undo an accidental tapped in the wrong place that makes this appear to have been the solution. the real solution was more complex. When I initiated iCloud, several of my email accounts showed up as duplicate accounts both in the accounts preference pane of system preferences in the mail preference pane under mail accounts. Deleting the duplicate instances of these accounts and rebooting the computer did not work the first time, but after additional reboots done in the service of other troubleshooting requests, the problem was solved. Paragraph please excuse the irregular capitalization because dictation is not perfect on the phone.

As I wrote below, this turned out not to have been the correct answer. It was selected as the correct answer accidentally. I nevertheless appreciate old toads contributions very much, as the things that he suggested were also the first things that Apple support suggested. So he was on target but the problem was actually weirder than originally anticipated.

Thanks for the thoughts.

No cleaners, optimizers, virus scanners etc.

Still happens in safe mode, starting up wifi on or wifi off.

I currently have five mail account active on my Mac, which are based on four different servers. I don’t think I have any smart mailboxes. Maybe this is the issue?