Windows 10 Search can't find ANY applications. Even calculator

Here is the relevant part:
I reinstalled Cortana using the following procedure:
  1. Open an elevated Command Prompt window (press win + X, and then press A)
  2. Type start powershell and press enter
  3. Run the command (in one line):
Get-AppXPackage -Name Microsoft.Windows.Cortana | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
After 30 seconds or 1 minute the problem was solved on my machine. Incredible.