Start by using system restore, and revert to the point in time prior to installing NiK4.
With NiK removed, perform some maintenance.
Elevated command prompt or powershell
chkdsk c: /r
(select “Y”) to run at boot time
allow this to run, will show no integrity violations found… found corruption and repaired them, or found and cannot repair. (let us know the result)
If no issues are found, continue with .Net Repair. If issues are found and corrected, Restart your system
Now run the .Net Framework repair tool:
Download Microsoft .NET Framework Repair Tool from Official Microsoft Download Center
-Restart your system.
If errors were found above (either command) run again and confirm no more issues with System File Checker or File System.
-Run windows Update (restart again if needed)
Download a fresh copy of the NiK Installer, run again and test.
If you are not able to complete the steps above, let us know and we can advise further.
If you have the installer log (with failures) for NiK, posting this might also help. They can be found here: