After I updated my Mac to Mojave, the mail app became very slow, particularly with the rules.
I have rebuilt mailbox, restarted Mac and Mail multiple times.
My account connects to MS Exchange.
It takes ages to open rules, scroll down and add new senders to a rule I have created to mark "spam" and move all emails from this sender to junk folder. I have checked today, and to run the rule on one email takes about 1 minute. Any ideas?