mail search completely broken in Catalina

Safe boot resolved this issue.

OS update 10.15 solved the issue for me. No further action was required.

The latest update 10.15.1 fixes the problems. I've got back my flagged emails, and the search works fine. RELIEF!

Do you just have Catalina installed, or do you have Catalina installed with another Mojave volume? In the latter case, it hoses Catalina Mail search, and special steps will need to be taken to get Mail search working correctly on Catalina. If this is the case, I will post those steps.

This solved my problem. My search was broken too. I followed the stop/start spotlight as mentioned in the post above and the search is gradually coming back to normal. I think Spotlight needed a kick to get moving.

Summarizing from the link:

1) Launch the Terminal.app (Just copy/paste the string starting with sudo.... and press return)

2) Stop Spotlight and remove the indexing: # sudo mdutil -i off -E / <return>

3) Enable it again by typing: # sudo mdutil -i on / <return>

Mail was screwed up after Catalina upgrade, and I followed the advice of

some smart fellow who said:

hold the Shift key down and start Mail,

quit Mail and do the shift key start Mail again.

Quit Mail.

Reboot the Mac (MacBook Pro 2015), run Mail -

fixed.

I also did a Rebuild on each Mailbox, and to be sure, did a Disk

Utility First Aid as well. Back to normal. What a pain.

Search was not working, in Mail Preferences I disabled all my accounts, quit Mail, restarted Mail, enabled all the accounts, Quit and Restarted, Search working perfectly.

Wiping my computer back to High Sierra, updating my way back to Catalina and then restoring a Catalina Time Machine backup via Migration Assistant seems to have fixed the problem. Easy, if you can waste a day.

Deactivating and activating Gmail worked for me. Thanks.

Thanks edgmiw This worked for me. When re-opening Mail it worked through re-indexing and seems to have solved it. Will wait and see what happens tomorrow!

I just did a restart and it is now working.

The shift-click twice and reboot worked for me. Just to note, the mail window did not open up so I had to cmd-Q to quit, and then after the restart go File->New Viewer Window. Thanks edgmiw.

Yep, Catalina 10.15.1 resolved this for me.

Ok, finally. I reset the PRAM, the SMC, with the latest update to Catalina. Search is working again.

Yep, the shift-click reverted to not working, but the issue was solved with the 10.15.1 update.

Deleting the "Envelope Index*" files did the trick for me.