I recently upgraded to Monterey v12.6 from the most recent version of Big Sur. I did a clean install of Monterey, then migrated all of my data from a backup of my Big Sur system. It was several weeks after upgrading that I tried searching for an event in Calendar and discovered that no matter what I searched for, no results are found. Search was functional under Big Sur.
I’ve googled the problem and the general solution is to either rebuild spotlight for the folder ‘user/Library/Calendars’ or for the whole disk. I’ve done both and still don’t get any results when searching in Calendar. I do find calendar events when using spotlight in the Finder, so I don’t think Spotlight is the problem.
Any suggestions of how I might fix this problem? (I do have one remaining backup of my Big Sur system, where search was working and wondered if copying its 'user/Library/Calendars’ folder over that same folder in Monterey might fix things. I haven’t added that many calendar events since upgrading, so I would not be missing many new events since the upgrade.)