I think many Windows 10 users encountered issues with the Search box under Cortana at one time or another. I personally encountered it under different manifestations.
The most common is when Search is not working at all.
There are few solutions proposed elsewhere, all useful and which should be verified any time this sort of problem is encountered.
1. Re-register Cortana with PowerShell
Get-AppXPackage -Name Microsoft.Windows.Cortana | ForEach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\AppXManifest.xml”}
This alone will fix most issues.
2. Reset the Control Panel Indexing Options. I will not insist for the method applied here, as rebuilding the index is supposedly known from Windows 7. Also verify the Indexing locations and reset comparing with a clean installation. There are registry keys which can be reset to trigger a “clean install” of the indexing options.
Delete
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search\CrawlScopeManager\Windows\SystemIndex
You will need to take ownership and reset permissions in the registry for this to work. If you do not understand this procedure, do not do it. Leave the indexing alone and only rebuild the database.
The new method for fixing Cortana Search which I could not find on any web site and was discovered by me following few days of research is to reset the Cortana cache per user.
This applies when for example new Language Packs are installed or uninstalled. In Australia we use the US base OS and the UK Language Pack used with the US keyboard if we are to follow Microsoft’s new rules starting with Windows 8. It is much easier to use only the US Language Pack, but the UK Language Pack (not available before Windows 8) is pushed automatically from Windows Update if there is no additional configuration done early after the installation.
Or even when upgrading from one version like 1607 to another like 1703.
The behaviour is more subtle in the sense that Search works, but none of the programs is launched from the Search box. Like in searching for cmd and trying to either launch or run As Administrator by right-clicking. Some functionality is working, while launching software is not working. The reason is that the Cortana cache per-user is corrupted and a full reset of the profile would fix the problem, but this is inconvenient in most situations.
The graceful solution without resetting the full user profile is:
1. Open Task Manager and kill Cortana (6 times seems to be the sweet spot, after which it will not restart, or at least not immediately).
2. Delete everything under
C:\Users\<username>\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy
without deleting the folder itself.
You may have to stop Windows Search as well. There may be a delay or you may need to browse under certain folders and delete folders sequentially, starting from the most inner folder.
3. Reboot
The folders deleted which are only part of a cache should be all recreated and Cortana Search should work as expected now.
Note: Cortana can be disabled in Group Policy (Enterprise, Education and Pro only). Search would still function and this has nothing to do with Cortana as Personal Assistant functionality, which is disabled by the Group Policy.
