I found the below guideline which says to go into ~/library/mail/V9/maildata to copy the messagesrules.plist onto the new Mac…
RE: can I export mail rules from one Mac … - Apple Community
…but even quitting & restarting the Mail app hasn’t picked up to apply the messagerules.plist
Did the configuration change? Or is something else needed (complete reboot, etc)?
Mac Studio, macOS 12.6
Thanks. That aligns with what I found while poking around. It appears that the two files have approximately the same content (opened both in TextEdit), but I wasn't about to go poke through line by line to figure out the syntax.
My own solution was to log back into the old Mac, open Mail Rules & copy/paste the Rule's basics & target email address into a text file, port that file over to the new Mac, open Mail, open Rules & create new Rules, using the contents of the text file. Transcribing in this fashion roughly a dozen rules & ~100 addresses took around an hour of touch labor.
FWIW, this apparently was a recent change in Monterey? Because my migration to what's now the "old" Mac was only done in Feb 2022 and worked out fine.
I can't say I've looked closely, but I don't think I've ever seen that plist.
I have a SyncedRules.plist and an UnsyncedRules.plist.
It may matter how you have your email accounts set up. All of mine are IMAP and synced.
Maybe that referenced plist is if you don't sync your email accounts.
But, I have no idea if it actually reads those files--they may just be backup stores for the database and would only be read if the database was rebuilt.
Migration of Apple Mail Rules to new Mac
