After installing Microsoft Windows 8 KB2821895 you may notice a few quirks. The first is that you might see the update is listed as having been applied – in multiple places. This seems innocuous but can be confusing.
The second issue is that running SFC directly or via other tools like the wonderful D7 from FoolishIT will report corrupt files in Windows that _cannot_be fixed. Thankfully there is a work around to this corruption reporting issue. From an elevated command prompt as depicted in the graphic, run the following Deployment Image Servicing and Management (DISM) command:
dism /online /cleanup-image /restorehealth
Once this dism process completes, you can rescan for Windows file integrity: