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What do I do if SFC detects but cannot fix a problem?

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I run Vista, SP2, Home Premium. The results of “sfc /scannow” show a couple of files that cannot be repaired. It couldn’t re-project a corrupted file; the source file in store is also corrupted. PublicKey neutral in the store, hash mismatch. Now, I don’t find this problem mentioned in your archives. I see the problem addressed on the web, but the various solutions presented seem either overly complex or too simplistic for me to comfortably try them. I see some people have tried these “solutions” that (after getting feedback that the files are restored) run “sfc /scannow” again and receive the same error indications. Is this a case of a problem that is not a problem? What are your thoughts? How would you proceed to restore these files?

The System File Checker (SFC) uses several techniques to detect that one or more of your system files have been either inappropriately replaced or damaged. SFC then tries to repair the problem.

Unfortunately, it can’t repair everything. In your case, that puts you in a hard spot.

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How do Windows files get damaged?

One of the most worrisome reasons is malware, which tries to replace or alter system components with its own malicious code.

Windows keeps a list of all of the system files and their characteristics. Among other things, that’s the “hash” that’s mentioned in the error message you received. If the files don’t match those characteristics, then SFC tries to recover those files from backup copies that Windows maintains elsewhere on your system.

Unfortunately, those backup copies can also become damaged or missing; the reasons why range from malware to an over-aggressive disk cleanup.

Even the database where the information is kept can also become damaged or corrupt. In these cases, SFC simply can’t do its job.

Healthy ComputerWhat can I do?

At that point, you have three options:

  1. Ignore the problem. It’s difficult to make a strong argument for this other than the next two options are painful. When would this be acceptable? Let’s say you’re not actually experiencing a specific problem; you just ran SFC for the fun of it. In that case, you might consider ignoring the problem. But it would make me uncomfortable and a little nervous moving forward. I would certainly run anti-malware tools at this point.
  2. Perform a Repair install of Windows. This isn’t always an option, but when it is, it can save you some hassle. A Repair install replaces all of the Windows components with the correct ones and keeps that SFC database up-to-date. You may need your original installation media or your copy of Windows for this to be a viable option.
  3. Backup, reformat, and reinstall Windows and all of your applications and data from scratch. Usually, everybody wants to avoid this option at all costs.

This last step guarantees that you’re back to the point where SFC thinks you should be: a consistent and proper copy of Windows. Nonetheless, it’s a very painful process to get there.

10 comments on “What do I do if SFC detects but cannot fix a problem?”

  1. Won’t SFC give the exact name of the problem file? If so, I would think you could go to the MS website, download a good version of the file for your OS, and replace the bad file. Admittedly, you’ll have to be careful when finding the file location.

    Ray

    • The MS website doesn’t have a database of downloadable files. There are some offered on third party sites, but those are potential sources of malware. Even in the case of sites which may have clean files, there is a good chance you’d get an incompatible version, as in some cases MS has different versions of files with the same name. In some cases, it’s worked for me to copy the corrupted or missing file from my Windows installation disk to the appropriate location. This doesn’t always work.

  2. I had a similar issue where I had at least one suspect problem system file and SFC couldn’t do anything to fix the problem. I took option #1 and ignored it because that was easier than the other options. Until the day when I got fed up. Then I took option #3.

  3. What’s the difference between SFC and a repair install from the Windows disc? SFC will sometimes even ask for the Windows disc to repair files.

    • A repair install of Windows replaces all of your Windows files, where SFC searches for and tries to replace any damaged or missing files. It is not always as effective as a repair install, and a repair install is not always as effective as a complete re-format and install.

  4. I ran SFC but it didn’t complete. It found corrupt files which it couldn’t repair. It referred to CBS.log. There are various lengthy CbsPersist logs but the mean nothing to me.

  5. Hello Leo,

    I have the same problem but in windows 7 Premium Home Edition ( x 64) Service pack 1, System install dat: 9/5/2011. Do they also have a 1386 folder ?

    Would anything in My Configuration.com be of any help ?

    Thank you for your help so far,very clear explications, asI am a complete hopeless computer user. I have subscribed on your newsletter.

    • Windows 7 does not have an I386 folder. You’ll need installation media or perhaps a recovery disk from the manufacturer. I’m not sure what you’re referring to by “My Configuration.com” – I’m only seeing unused domains if you’re referring to a website.

  6. If sfc can’t repair a corrupt file, and one’s computer otherwise runs fine, then yes, run a malware scan for sure. If that is clean, I would leave it alone. If you don’t know what you’re doing, you are more likely to cause more damage by attempting to fix something that doesn’t need fixing.

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