If you’re having trouble with Outlook 2016, specifically a mailbox not loading or search not working, an easy fix is to rebuild the Outlook Search Index.
Outlook is a complex program. In fact, it’s a few programs in one: Mail, Calendar, Contact Manager, and Task Manager. As you begin to use it and demand more of the program, issues can occur over time, such as rebuilding your PST file, migrating emails to a new computer, and adding new mailboxes. If you’re having trouble with Outlook 2016 and above not functioning properly — specifically a mailbox not loading or a problem with search – then a quick and easy fix is to rebuild the Outlook Search Index.
In this article, we will show you how to do that. If you are running Outlook 2013, be sure to check out our article for that version here.
Rebuild Outlook Search Index
Go to File > Options and select Search in the left pane.
Next, click the Indexing Options button.
Indexing Options will open up; click the Advanced button. Note that this step may require administrator privileges.
Next, on the default Index Settings tab, click the Rebuild button.
Do note that while the index is being rebuilt, searches probably won’t work, so wait until the process completes. The amount of time it takes to complete varies depending on the number of emails, file size, and processing power.
You can see the status of the process updating at the top of the Indexing Options window. If you have other apps running in the background, then you’ll see “Indexing speed is reduced due to user activity.”
Once the rebuilding is complete, you are finished. Go back in and do some searches and see what kind of improved speed and functionality you get.
Note: This works with modern versions of Outlook that are part of the Microsoft 365 (formerly O365) suite of Office apps.