Search in Mac Mail No Longer Working Properly

Nancy Trainer wrote:

I use the search function in Mac Mail all the time -- to remind myself about old e-mails that I've sent or saved (e.g. what was the name of that rhododendron that Mom recommended? What year was I e-mailing folks back and forth about Dacor appliances?). Suddenly those searches just show results that I know are wrong -- e.g. almost nothing shows up in the searches. For example, I search for the word "Leif", knowing that the guy who runs my kids' tennis program is Leif something and I've sent him tons of e-mails... and nothing shows up. If I start a new e-mail his name comes up immediately when I start typing "Leif," and there are definitely e-mails in my "Sent" folder with his name on them. Yet nothing shows up in the search.

HELP! This is a vital tool that I use all the time to remind myself of things I've e-mailed about. I don't want to lose it.

Mail search is dependent on the Spotlight data base...

Rebuild the Spotlight index on your Mac - Apple Support

Have this exact problem on both an M1 MBA and a intel iMac after upgrading to OS 12.0.1. Contacted AppleCare today nothing in their playbook offered a fix but I was told that this was an emerging bug of the new OS.

So hoping on a fix not to long from now.

Mail has broken in multiple ways I have noticed.... on both my Mac's the search is very broken (after Rebuilding Spotlight it appeared to help but I have noticed that it showed different results but not all) but I noticed that all my signatures were gone and went back to settings of years ago... suddenly old signatures were back and all new were gone. I also have found that the junk mail settings are not working as I have set it and rules I've put in place for spam are also not being followed by mail.

Rebuilding Spotlight seemed to make mail search on my iMac better (not completely perfect) but not on the M1 MBA