sfc /scannow ERROR - could not start the repair service

SOLUTION:
You're probably trying to run these commands from a 32-bit cmd.exe/shell/whatever. You need to execute these commands from a 64-bit console.

In my case, I used to start "cmd.exe" from a 32-bit File Explorer. No matter whether you go to System32/cmd.exe or SysWOW64/cmd.exe - it would start the 32-bit cmd.exe

Easiest ways:
a) Win+R, and enter "cmd.exe" it should start the 64-bit binary.
b) Using Task Manager or ProcessExplorer in 64-bit, "Run" the "cmd.exe" from there.
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C:\>sfc /scannow

Windows Resource Protection could not start the repair service.

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C:\>net start trustedinstaller
The requested service has already been started.

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C:\>Dism /Online /Cleanup-Image /ScanHealth

Deployment Image Servicing and Management tool
Version: 6.1.7600.16385


Error: 11

You cannot service a running 64-bit operating system with a 32-bit version of DISM.
Please use the version of DISM that corresponds to your computer's architecture.

The DISM log file can be found at C:\Windows\Logs\DISM\dism.log