One of the solutions to fix Outlook search issues is to verify the index. Start by opening Outlook, and then click on the search box when it opens. Select the Search Tools next and Indexing Status after that, all from the search menu. To resolve Search not working in Outlook 2016, new dialog will open with the title of Indexing Status, and it should say, “Outlook has finished indexing all of your items. 0 items remaining to be indexed.” Click on OK to close. However, if there are items left, wait for them to complete.
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