By default, in Windows 7 and Windows Server 2008 R2, the search functionality, from the Start Menu search box, does not search libraries that are not indexed. Even if you do try, you will notice that search result does not include libraries that are not indexed. As a result, you will not be able to use the Start menu’s Search box, to search files that are stored on network locations.

But if you want to add this functionality, you will have to apply and download a hotfix from KB2268596 and apply it. This hotfix will add the functionality to search libraries that are not indexed from the Search programs and files box on the Start menu.

To enable this functionality, you will have to  create a registry subkey after you install this hotfix.

To do this, open regedit and navigate to the following registry subkey:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\SearchPlatform\Preferences

Now in the right panel, right click and select New > DWORD Value.

Name it EnableSearchingSlowLibrariesInStartMenu and give it a value of 1.

Click OK and exit Registry Editor.

If you want to disable the functionality of searching libraries that are not indexed, set the value of the EnableSearchingSlowLibrariesInStartMenu registry entry to 0.