Posted on by Mac User

How to re index Outlook for Mac

Reindexing Outlook for Mac is the process of rebuilding the search index that Outlook uses to quickly find emails, contacts, and other items. Over time, the index can become corrupted or incomplete, leading to missing or inaccurate search results. Since Outlook for Mac relies on macOS Spotlight for its search functionality, reindexing involves refreshing both Spotlight’s index and Outlook’s internal database. This ensures that your searches return accurate and complete results, improving overall performance and reliability.

On the newer versions of Mac the have simplified the spotlight index option for outlook. Open up System Settings, spotlight drag the outlook bar to off then reboot, Log back in and re enable outlook in spotlight and another reboot. On this one log back in and open Outlook for Mac. If you find your still having issues, test the string search on the web version of your mail hosting server like exchange, google mail or Apple mail to name just a few. If the search is working correctly then Outlook for Mac has got some form of issue.

With the new version of Outlook for Mac you can try swapping it over so old Outlook (Classic which everyone seems to like) move over to new Outlook. Let it rebuild the mailbox so give it a few hours to go through the cycle. Once completed see how you get on, You can always then switch back at a later time. This option seems to be effective is fixing the indexing issue within Outlook if the spotlight option does not work.

Rebuild Spotlight Index for Outlook

If above does not work you can be more forceful and try target spotlight indexing. Allow up to an hour for reindexing to complete.

Open System Settings → Siri & Spotlight → Spotlight Privacy.

Click + and add the Outlook data folder:~/Library/Group Containers/UBF8T346G9.Office/Outlook

Restart your Mac.

Go back to Spotlight Privacy and remove the Outlook folder.

This triggers Spotlight to reindex Outlook data. You can try another reboot it won’t hurt.

Older Macs try this method:

Open  System Preferences  older macOS.

Go to Privacy & Security → Spotlight Search → Privacy 

Click + and add your Outlook profile folder:

~/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/

(Use Finder → Go → Go to Folder… to paste that path and find your profile; by default the profile folder is “Main Profile”.)

Wait ~5–10 seconds, then select that folder in the Privacy list and click – to remove it. Removing it forces Spotlight to reindex that folder.

Wait for Spotlight to reindex — this can take minutes to hours depending on mailbox size. You can watch indexing progress in Spotlight (sometimes a small progress bar appears). 

Terminal (more precise) — reindex the Outlook profile with mdimport / mdutil

Use this if the Privacy trick didn’t help or you want to reindex only the Outlook profile.

A. Confirm Spotlight importers are present

  1. Open Terminal (Finder → Applications → Utilities → Terminal).
  2. Run:
mdimport -L

If you see more than one Microsoft Outlook Spotlight Importer.mdimporter, remove any duplicate Outlook installations (delete the older app, empty Trash), restart, then run mdimport -L again. Microsoft recommends ensuring there’s only one importer. Microsoft Support

B. Reindex a specific Outlook profile (Microsoft’s command)
Replace <user_name> and <my_profile_name> with your short macOS user name and the profile name (e.g. Main Profile):

mdimport -g "/Applications/Microsoft Outlook.app/Contents/Library/Spotlight/Microsoft Outlook Spotlight Importer.mdimporter" -d1 "/Users/<user_name>/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/<my_profile_name>"
  • -g loads the Outlook Spotlight importer.
  • -d1 runs mdimport at debug level 1 for the profile path (this forces import/reindex of that folder). Microsoft Support

C. (Optional) Full Spotlight reindex for a volume
If you prefer to rebuild the entire Spotlight index (slower, more invasive):

sudo mdutil -E /

That erases (E) and rebuilds the index for your startup volume. Use with caution — full reindex can take hours. For more control, you can run mdutil -s / to see status.

OutlookSearchRepair utility (only if available)

Microsoft used to publish an OutlookSearchRepair utility that automates reindexing for Outlook. It still exists in some environments, but it may not work on newer macOS versions — check compatibility before using. If it’s available for your environment, it typically:

  1. Detects duplicate Outlook installations, asks you to remove duplicates.
  2. Offers a Reindex button and shows progress; wait until it reports “Done! Reindexing has completed!”

If reindexing still doesn’t fix search (Last resort)

  1. Confirm your profile name has no special characters (slashes etc.). If it does, rename the profile folder under:
~/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/

Microsoft lists this as a recurring cause. 
2. Try creating a new Outlook profile (Outlook → Preferences → Accounts → add a new profile) and let it fully sync — if search works there, your old profile’s index/database may be corrupted. Microsoft Support
3. If nothing works: uninstall and reinstall Office for Mac (after backing up any local data), or contact Microsoft support. 

Quick troubleshooting tips & expectations

  • Reindexing can take a long time for large mailboxes — be patient and avoid toggling search/UI modes while indexing runs. 
  • If you use the new Outlook UI vs legacy Outlook, try toggling the UI and checking search — some versions behaved differently; ensure you’re on the version supported by Microsoft for search. 
  • If you see “No Results” but indexing is in progress, wait until indexing finishes before concluding it failed. 

Useful commands summary (copy/paste)

# show installed Spotlight importers
mdimport -L

# reindex a specific Outlook profile (replace user and profile name)
mdimport -g "/Applications/Microsoft Outlook.app/Contents/Library/Spotlight/Microsoft Outlook Spotlight Importer.mdimporter" -d1 "/Users/<user_name>/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/<my_profile_name>"

# check Spotlight index status for / 
mdutil -s /

# erase & rebuild the index for /  (full reindex)
sudo mdutil -E /

Final thoughts:

If your having indexing issue that lead to a re create of the outlook profile within the users library and it still does not work you may need to either delete the outlook profile and start again by re adding the mailbox to a clean outlook profile. You an also try a new user name profile and load the mailbox to Outlook on the new user. Outside of this I would recommend the machine needs a factory reset and wipe to start again. I would not recommend a Time machine restore as it will only bring back the old legacy issue. Sometimes a clean brake is more reliable.