Problem with Apple Mail in Ventura

Since installing Ventura, many times, every month, on starting up my Mac, I get the following message:
Mail cannot access your mailbox information because it’s already in use.
Another application on your computer or on your local network is using your mailbox information. Click Quit to quit Mail. Then log out of this computer and any other computer you’re using. After you log in again, open Mail on one computer only.

If this message reappears, there may be a network server problem. Contact your system administrator to determine if it can be resolved by rebuilding your mailbox information. Then click Rebuild Mailbox Information.

Rebuild Mailbox Informatio Quit
Sometimes I press the Quit button and launch Mail; other times I do the Rebuild Mailbox Information button. In either case usually either works and Mail works. Other times I repeat with the other button.
This happens since installing Ventura.
My Mac is an iMac (Retina 5K, 27-inch, 2017).
Has it happened to anybody else?