Problem
I've created a smart mailbox in macOS Mail for "Unread" messages with the following rules:
Contains messages that match all of the following conditions:
- Message is in the mailbox: Inbox
- Message is unread
The smart mailbox will always correctly include unread messages in my inbox. But often, it will incorrectly include read messages in my inbox. Any ideas on how I can fix this?
Other information and troubleshooting steps so far
- Currently using macOS Sierra 10.12.6
- Email account is hosted by Google
- Other smart mailboxes with other rules still work properly.
- If I use the filter button in my inbox, Mail will properly perform filtering -- even for unread messages.
- I tried marking the problematic messages as unread and then as read again. Afterwards, the number next to the title of the "Unread" mailbox will decrease (because I have taken steps to mark messages as read), but the "Unread" mailbox itself will still list those messages (even though they are read).
- I tried the above step from gmail.com. Same result.
- I tried getting new mail. Nothing changes. I tried rebuilding my mailboxes. No rebuilding happens.
- I tried rebooting my computer in safe mode. Then, any smart mailbox I created would contain no messages regardless of the rules I set.
- There doesn't seem to be any pattern to which messages are problematic.
- My "Unread" smart mailbox still behaves properly for non-problematic messages even if it contains problematic messages.
- Once a problematic message appears in my "Unread" smart mailbox, it will stay there for a few days. Then, it will suddenly leave "Unread" and sit in my Inbox where it belongs.
