Near-duplicate items aren't listed in SharePoint Online or SharePoint Server 2013 on-premises search results
In SharePoint Online or SharePoint Server 2013 on-premises, you search for an item that has a near-duplicate file. Both files are located in SharePoint. When you view the search results, only one of the items is returned.
To resolve this issue, enable the Show View Duplicates link option, or change the query rules to show duplicates on the search center page. To do this, follow these steps:
Browse to the search center by searching the Everything scope.
Click the gear icon, and then click Edit page.
Click the drop-down arrow in the upper-right corner of the Search Results Web Part, and then click Edit Web Part.
Use one of the following methods, depending on your preference:
To show the View Duplicates link: In the Search Results Web Part properties box, expand the Settings section in the Properties for Search Results section. Then, select the Show View Duplicates link check box, and then click OK.
To enable Don't Remove Duplicates: In the Search Results Web Part properties box, click Change query in the Properties for Search Results. Click the SETTINGS tab. In the Remove Duplicates section, set the value to Don't Remove Duplicates, and then click OK. Then, click OK in the Web Part properties box.
After you change the search results page, click Check it in on the ribbon, and then click Continue.
Click Publish this draft on the ribbon to publish the page to users.
NOTE You cannot change the site collection search page by using these steps in SharePoint Online. These steps apply only to the Search Center site.
For more information about the Search Center in SharePoint Online, see Manage the Search Center in SharePoint Online.
For more information about the Search Center in SharePoint Server 2013, see Set up a Search Center in SharePoint Server.
Still need help? Go to SharePoint Community.