These are the steps, I always repeat after migrating accounts to new machines to fix Outlook/Spotlight issues. Not my genius, just the extract of webhints and some trial and error. Since 10.14 I performed these steps successfully on a ton of Macs. First steps: Ask Spotlight to re-register all installed search plugins. Kill dock (I don't know why, but it doesn't hurt and restarts immediately). Re-enable indexing. Second steps: Delete Outlooks sqlite database, it will find out and rebuild. Start Outlook, it will perform a auto-repair. On large accounts, take care of available disk space before. After these steps, Outlook/Spotlight will perform together again. New on Monterey: Upgrade from 12.01 to 12.1. Outlook search broke again. Used the simple Spotlight privacy add/remove steps. Spotlight started indexing, Outlook search is working again. These are the steps I use to fix the issue: Quit Microsoft Outlook! Perform these steps in the terminal (admin permissions needed): sudo /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -seed -lint -r -f -v -dump -domain local -domain system -domain user -domain network killall Dock sudo mdutil -E / Navigate to (replace "YOURPROFILE" with the profile name you need to fix, i.e. "Main profile"): ~/Library/Group\ Containers/UBF8T346G9.Office/Outlook/Outlook\ 15\ Profiles/YOURPROFILE/Data and move the file "Outlook.sqlite" to the trash. Start Outlook. It reports, that it needs a reapir and starts rebuilding its database. Wait upon completion, Outlook comes up again. Some patience needed, until Spotlight has finished indexing. If Spotlight still doesn't love it (see notes above, 12.1 update), add YOURPROFILE to Spotlight privacy and remove it. I use these steps as a common routine after migrating/upgrading Macs to fix the Outlook/Spotlight issue, nevertheless try at your own risk. Edit: On large mail accounts, Outlook needs a while to rebuild. 100 GB may take an hour or more to finish, depending on the speed of your machine/disk. Show information of the YOURPROFILE folder, to get its size prior rebuilding. Be sure, there is enough disk space for a rebuilt. After completion, you should trash the backup copy.