Sometimes you face problems with Windows Store after upgrading to Windows 8.1.
To fix the issue generally it is recommended to run WSreset.exe tool, or manually trying to clear the cache from the Windows\SoftwareDistribution\Download folder.These two methods are used if you like to re-register Windows Store. So here you can fix the issue via Command Prompt.
Open the Command Prompt as Administrator. Now type in or, copy and paste the following:
powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\WinStore\AppxManifest.xml
Press the Enter Key.
Now type in or press the following command:
start "" "ms-windows-store:"
Press the Enter Key. That’s all.
You can apply the same for Windows 10 Technical Preview also.