Explained: How and Why Windows Goes Corrupt

I've been repairing computers now for over 23 years and for the last few years, I began offering my computer repair service online. One of the most popular repairs I do today is to fix Windows Update; sometimes, however, Windows Update is too far corrupt that it requires a complete reinstall of Windows in order to fix the issue. The same can be said in other situations where Windows is too far corrupt that it cannot be repaired even by someone with as much experience as I have. Based on this, users ask me "Why is my Windows corrupt?" and "How can this have happened?" I thought I'd write an article explaining various ways Windows can go corrupt. Note that the list below is not exhaustive, but will certainly shed some light.

Update 20200116: I'm getting a lot of emails from folks asking for help on this. If you want this problem fixed ASAP, send me an email and don't forget to leave your phone number. I will call you back as soon as possible.

Loss of Power and Improper Shutdowns

One of the easiest ways to corrupt Windows is to lose power to the computer (especially while it's updating, for example). In a case like this, system files may in the process of being updated; if the process does not complete 100%, what you end up with mismatched or corrupted binary files. The same can be said if you do not shut down the system properly (by clicking Start, then shutdown). Oftentimes the system will be updating itself in some way or another (even if it's not explicitly stating so); if you shut down without properly notifying all programs of the impending shutdown, you stand a chance of corrupting files. Most of the time, files can be corrected by scanning the drive for errors, however, this does not always work and then strange things start to happen.

Antivirus Software Conflicts with Windows

It's a well documented fact that Antivirus software can conflict with Windows Updates, which can corrupt the system to the point Windows won't even boot, or it might break certain parts of Windows entirely. For example, I've personally witnessed Antivirus software interfering with parts of Windows that prevented the Windows Start menu from functioning. The only way to get it back was to disable the antivirus, then initiate some patch work (using the Power Shell) to reinstate / reinstall broken Windows Services, however, this does not always work.

A Bad or Failed Windows Update

It's also a well documented fact that Microsoft has released Windows Updates in the past that have then caused Windows to break. Sometimes it's parts of Windows that stop functioning properly (certain services) or strange bugs will appear, or the system may go completely corrupt to the point where you need to reinstall Windows. I have personally witnessed on my own machine a Windows Update that appeared to have wiped out my master boot record. This caused the machine to freeze just before booting into Windows. The only way to fix it was to restore a backup.

Registry Cleaners and System Optimizers

Some (most) "registry cleaners" and "system optimizers" are pure snake oil. They promise to "clean" the system, but instead make things worse by deleting registry entries or modifying Windows services that should not have been modified or deleted in the first place, which then causes Windows to corrupt. Another thing many "system optimizers" do is stay resident in memory (in the background), which then scans all activity on the computer, which then slows you down even more. It's completely unnecessary. My advice is that you steer clear of these programs - Windows works just fine 9 times out of 10 on its own. If your computer is slow and you want to address a specific issue, hire a professional to go in and look at it and tell you why and how to fix it properly.

Remnants of a Malware or Virus Attack

Oftentimes, malware and viruses will attack operating system files in an attempt to infect files and hide itself so that it can stay resident in memory. Unfortunately not all antivirus and antimalware programs can clean infected files 100% of the time. What you end up with is a system that is half clean, somewhat operational, but corrupt due to an infection that was not removed properly. In cases like this the only way out is to backup and reinstall Windows.

Hardware Failures

In rare cases there are hardware failures which can corrupt system files, but most of the time a hardware failure results in system instability, either way you look at it. For example, the system might be completely fine for a few hours and then all the sudden it will act erratic and freeze up. The only way "out" is to forcibly power off the system in order to reboot it, but as I mentioned previously, unclean shutdowns like this can also lead to corrupt operating system files. Aside from that: if the system is not stable, the only way to diagnose a hardware failure is to do a clean install of Windows, anyway, then perform various tests on hardware through process of elimination. Some users may use various methods for testing hardware, but it depends on what the problem is. 9 times out of 10 a clean reinstall of Windows is necessary.

There are other reasons why Windows can go corrupt, but these are probably the most popular. I hope this helps.

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I need more computer questions. If you have a computer question - or even a computer problem that needs fixing - please email me with your question so that I can write more articles like this one. I can't promise I'll respond to all the messages I receive (depending on the volume), but I'll do my best.

About the author: Dennis Faas is the owner and operator of Infopackets.com. With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.