If you have installed the update KB2821895, and then run the System File Checker using the command sfc /scannow, the scan reaches 100% complete, and you receive the following error:
Windows Resource Protection found corrupt files but was unable to fix some of them. Details are included in the CBS.log windir\Logs\CBS\CBS.log. For example C:\Windows\Logs\CBS\CBS.log. Note that logging is currently not supported in offline servicing scenarios.
The system file repair changes will take effect after the next reboot.
Open an elevated command prompt.
From Start, swipe in from the right and select Search, and type command prompt (or just start typing if you are using a keyboard).
When Command Prompt appears in the search results, tap-and-hold or right-click it, and select Run as Administrator
Type dism /online /cleanup-image /restorehealth, hit Enter, and wait for this command to complete.
Run the sfc /scannow command again until the command completes and reports that there is no corruption.
If you still get an error that there is corruption after following the above steps, you should contact technical support for further assistance as your system may have actual corruption.