Search broken in Apple Mail (so Smart Mailboxes also don't work)

I had this and I've no permanent fix for you I'm afraid. I think it's a rare bug that few people see, in spite of there being lots of advice about it scattered around the web. I too tried re-starting Spotlight, deleting indexes, dragging HD in and out of Spotlight, safe modes, new User IDs, and other stuff, but nothing worked permanently. Killing corespoltlightd was the easiest thing and it worked occasionally, but I wouldn't call it a fix.

It fixed itself when I got a new Mac, although my one remaining Smart Mailbox is still a tad slow to respond. I guess this is more likely to be because my 2023 MBP is masses faster than my 2015 MBA than because the problem has been fixed.

If Smart Mailboxes are very important to your workflow (they're not to me) then there are probably better mail clients out there, but if they use Spotlight as their search engine then you'll still have the search problem.

Sorry not to be much help, but it's always good to know you're not alone.

Best of luck.

Thanks. Looks like I am SOL on this one. This is one of those things where I suspect someone at Apple knows what particular plist or other file I have to ditch but we will never hear about that. Thanks anyway.

You say you stopped and started Spotlight, but have you tried rebuilding the Spotlight Index?

Rebuild the Spotlight index on your Mac

Yes, I neglected to mention that, I have also rebuilt Spotlight indexing (several times), particularly in concert with deleting the envelope index files in Mail in the Library.

I have experienced this behavior on occasion. Restarting my Mac fixes it until the next time it happens. I suspect some sort of bug chewing on code.