I need to add a new rule to Mail.app. I can enter it, close Preferences pane, reopen Pref’s pane and it’s still there. But if I close Mail, it’s no longer there.
Sorry, this is probably not related to SpamSieve, but I hope someone has seen this before and fixed it.
Yes, this is not related to SpamSieve, but I see it a lot because people (used to) need to set up a rule to use SpamSieve.
The most common cause of this is a bug with Apple Mail’s iCloud rule syncing. If you don’t need to sync your Mail rules with another Mac, you can work around the bug by turning off syncing. Open System Settings, click on Apple ID, click on iCloud, click on iCloud Drive, click on Apps syncing to iCloud Drive, then uncheck Mail.app.
The other cause I’ve seen is if there are bad file permissions/ownership/ACLs so that Mail doesn’t have write permission to modify the file
~/Library/Mail/V10/MailData/SyncedRules.plist. You can clear ACLs by giving the Terminal app Full Disk Access, then entering this command in Terminal:
sudo chmod -RN ~/Library/Mail
It was apparently the iCloud sync.
I appreciate your message even thought outside the SpamSieve realm.