SFC /scannow will fix Windows system files corruption. When it works by copying cached files stored after having been copied in the past (…system32\dll cache folder).
However, when the cached file is corrupted as well, it won’t work. Then you get a message like:
photocredit gHacks.net
SFCFix from The Tech Cookbook will fix that (it’s also a portable .exe). You should read the linked page.
How it does it is explained there (sort of) as well as in the gHacks article linked.
You must, however, run sfc /scannow first (to give it the CBS.log file to parse).
To run sfc /scannow:
- Tap on the Windows-key, type cmd.exe, right-click on the result and select "run as administrator" to open an elevated command prompt.
- Type sfc /scannow and hit enter.
- The process checks all protected system files for corruption and attempts to repair any files that are corrupted.
After this has completed, then run SFCFix on the system. It can take up to half an hour to complete (depending on the nature of the corruptions). Its actions will be recorded in a notepad document including the full path of each corrupted file it fixed.
Please note the following:
1. Since the files might have been corrupted by malware, you must first clean the malware off your system. Do this BEFORE running the sfc /scannow.
2. Since it’s not 100% clear just how the tool works, it would be VERY smart to make a full backup before using it.
3. If the tool doesn’t fix the corruption make sure to read the bottom of the page I linked above where you can download the tool. It gives a free forum (and a link to posting instructions) where you can post the notepad message and get further help.
Sources:
1. http://www.ghacks.net/2015/11/06/sfcfix-comes-to-the-rescue-when-sfc-scannow-cannot-repair-windows-file-corruption/
2. http://thetechcookbook.com/automatic-sfc-corruption-repair-sfcfix-exe/ <—Also the download page for SFCFix.exe. This page should be read before using the tool.