Gmail search operators not returning expected results

Question

I'm trying to filter out unread messages that are not in my inbox, and thought that -in:inbox in:unread should be sufficient. However, this is returning some (but not all) emails that are in my inbox.

Is there anything about these emails that's likely to be a bit weird? Like the one in the example below, they don't have any other labels attached to them

Answer 1

Instead of in:unread it should be is:unread.

Reference

• Search operators you can use with Gmail