When you run the System File Checker using the /Scannow parameter from an elevated Command Prompt, the following error may occur. Additionally, you may experience problems running Windows Installer Setup files and installing fixes from Windows Update.

Windows Resource Protection could not start the repair service

This happens if the TrustedInstaller (Windows Modules Installer) service is disabled. Use these steps to reset the service startup type.

1. Click Start, type Services.msc

2. Double-click Windows Modules Installer

3. Set its Startup type to Manual

4. Click OK.

The TrustedInstaller service has full access to Windows Resource Protection (WRP) files and registry keys, and this services needs to be running in order to restore missing or corrupted WRP resources. The TrustedInstaller service starts on-demand when running the System File Checker.

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  1. asdf
    said this on Tuesday, May 26th 2015 11:36 pm

    It seems to be set to ‘Manual’ by default. I just did this on a clean install of Windows 7 Professional 64-bit, and it was already set to manual. That also means that this isn’t the thing preventing me from doing the things from your “How to Run the System File Checker (Sfc.exe) Offline in Windows 7 and Vista” article, it’s something else :/

  2. Scott
    said this on Monday, December 15th 2014 4:20 pm

    Something worth noting…in vista the trustedinstaller service appears as Windows Module Installer. So when looking at the services you need to check if the Windows Module Installer has been disabled. I spent hours working on this because I was looking for a service called TrustedInstaller. :(

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