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Why Do System Cleanup Utilities Report So Many Errors on a Supposedly Clean System?

Question: I have a couple of good cleaning programs to protect my computer (which are usually recommended by you!). But occasionally, I get suckered into running a ‘free trial’ of a program (like a registry cleaner). I may have just run my cleaner and have been given a clean bill of health, but when I run the ‘free trial’, I invariably get hundreds of errors. Why?

What you’re experiencing is what leads me and many others to avoid recommending entire classes of registry and system-cleaning utilities.

It’s not just a few bad apples that spoil the entire bunch; in this case, it’s often difficult to find an apple worth biting into at all.

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  • Presenting lists of errors when there actually are none is a common sales tactic.
  • Even when not misleading, there can be differences of opinion on exactly what or how important an “error” might be.
  • Avoid these programs and tactics. They’re simply not safe.

The scare tactic

The most common reason trials reports lots of errors is simple: they want to scare you into purchasing their product to clean up what they supposedly found.

I say “supposedly” because the most disreputable scanners — and there are a lot of them — aren’t above lying.

Free Trial!They’ll report errors that aren’t actually present, and when you do purchase the program, suddenly those errors are no longer there. It’s not because of their exceptional error correction technology; it’s because in reality, the utility did nothing at all.

Many of the utilities that do clean things are still not above overstating the risk of what they find.

For example, some may claim having a thousand cookies is a very serious performance and security risk. In my opinion, it’s neither, and is nothing you need to act on. But if you buy into their rhetoric, you’ll be convinced you need to purchase their product to clean it all up, which they then do.

Which brings up the second problem with these cleaners.

Differences of opinion

Ask 100 tech pundits about this topic and you’ll get 100 different opinions.

The same is true for the creators of system-cleaning software. Even among legitimate programs, a wide variety of opinions exist about what is and is not an “error”, what is worthy of cleaning, and what can be cleaned safely.

The net result is that you could run one legitimate program to completion, have it report that your machine is now 100% clean, and then immediately run a different legitimate program, which might report that it’s still riddled with cruft.

There’s no absolute measure of which of them is “right”.

There just isn’t a formal definition of what it means for a machine to be “dirty”. Oh, there are common things that most would consider as dirt, but once you stray out of that list, things quickly become unclear.

And even on those items that everyone considers technically “dirt”, you’ll find a variety of opinions about whether there’s any value in cleaning it up.


The biggest piece of advice I have is to resist the temptation to try the latest and greatest system-cleanup utility or registry cleaner’s free trial. Just don’t.

At a minimum, only run tools you’ve heard of and that have a good recommendation from people you trust.

If you’ve never heard of it and the only words in support are from the tool’s own site or advertisements, walk away.

The potential for harm or just wasting your time and money is just too great.

My recommendation

Besides using only trusted tools, my single biggest piece of advice is simply this: don’t go trying to fix problems you don’t actually have.

Put another way, I ignore cleanup utilities entirely until I’m actually experiencing a problem. Only then will I consider using a utility, and even then, I’m more likely to target the specific problem rather than use a more general purpose “fix everything” utility.

But that’s just me.

As I said, there are many opinions on this. If you do elect to invest in a cleanup utility, I strongly suggest you do the research first to find out if it’s worth what you’re about to pay for it.

While it’s possible it is, more often than not, it simply isn’t.

And, of course, make sure to back up completely first, before running any cleanup utility. You know … just in case.

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28 comments on “Why Do System Cleanup Utilities Report So Many Errors on a Supposedly Clean System?”

  1. A recent article in PCWorld magazine took a look at cleanup utilities from another angle: PC speed improvement. In an article entitled, “Cleanup Utilities: Can They Speed Up Your PC” (August 2011 issue), the conclusion reached after testing was that “in most cases the cleanup utilities scarcely made a difference in overall system performance.” After running a utility, “your PC’s overall performance is unlikely to change much.” The magazine’s advice was to uninstall old programs and save your money for hardware upgrade instead. The magazine tested four popular cleanup utilities (Ashampoo WinOptimizer 7, Iolo System Mechanic 10, Piriform CCleaner, and 360Amigo System Speedup) on five well-used PCs of various specs and generations. The test results surprised even the magazine. Perhaps another reason, in addition to those stated by Leo, for PC users not to be so eager to use system cleanup utilities.

  2. if i use them it’s only to clean cookies and system temp and browser cookies and temp internet files. i never use them to do a system clean or reg clean i don’t touch that area at all.

  3. Yes, “context-sensitive ads” can be a bit… “interesting”. The ad I see is for one of those “speed up my PC” utilities.

    What gets me are those TV ads with people claiming that the (supposedly-free) utility made their systems faster than when they first bought the system, along with claims that spam and popups can cause “permanent damage” to your computer. (I’m sure you know what I’m talking about, but I don’t want to mention names here.) I did a little checking into several variants of the same utility under different names, and while every malware scanner gave the free utility a clean bill of health, all the free utility did was a registry scan. (It didn’t even include a “registry cleaner” in the free program.) It did absolutely nothing about looking for malware or other issues. For that, you had to buy their rather expensive “remote support” service, and allow one of their “techs” to remotely access and “clean” your system. I understand that that service was something in the order of a few hundred dollars.

  4. This reminds me: One time my mom’s computer was perfectly fine — I know because I was using it for something just the day before. Anyways, she saw a banner ad for a registry cleaner and decided to install it.

    Long story made short, it trashed the system. I was able to fix it so the computer would actually run, but still had to reinstall the OS because it didn’t run properly.

    Shortly afterwards, I installed Firefox + AdBlock Plus for her.

  5. I learned the hard way about using registry cleaners. What i use and like the best is CCleaner, i use it to clean cookies only i wont use it to clean my registry. Simple reason not to use a registry cleaner is, there is many shared dll files that if removed could make other programs not work. The only way i would recommend using a registry cleaner is if you know what you are doing and know what is safe to remove.

  6. If I had a “cleaner” program for sale, and were of a mind to try to bilk people out of their money,|I would include in the free download a standard video that looked very official and showed my software apparently finding lots of problems. After all, who really reads all that? And who knows enough to dig through the code to find it? (hint: usually not the people who would fall for such things) Then, of course, once my software was actually purchased, it would play another video of all those problems being fixed. The innocent and naive customer would be relieved that my software fixed all of the “problems,” I would be richer, and in most cases no one would be the wiser that my software actually did nothing. People are easy to con because A) Everyone wants something for nothing, and B) No one wants to believe they have been conned, once they actually have. So they fool themselves. “Hey, look, this app/page/whatever NEVER used to open this fast!”

    I am, by the way, pretty convinced that this is the way many of these free cleaners operate. If I can think of it, you may be sure many other people who are far less scrupulous than me have as well.

    I am always very wary of the sites that offer “free” anything and have lots of banners and ads for other things that are obviously bogus. People I know say “Oh, yeah, the ads are bogus, but the actual product is legit!” Yeah, right.

  7. I have a few cleaners, what I do is run all of them one by one without removing errors.
    The number of errors vary to such an extent it becomes unimaginable.In one cleaner it was just about a screen length 30-35 errors, in other it was mote than 500 or so errors.Just the cleaner I have is free it does not matter, I clean form all the 4 I have.
    It is clear way of making a aggressive sale for their product that this many error comes. I have heard that some cleaners are virus oriented, they contain virus or infect the computer being cleaned by the virus.

  8. I don’t mind some utilities help in cleaning jobs like temp files and left-over internet clutter. But I did learn long ago that registry cleaners are risky business. They can cause certain programs to stop working correctly. It’s on their tech help sites so i don’t mind sharing, but every Roxio Media Creator I have ever used fro 6 to present was harmed by registry cleaners. With programs looking for ‘security risks’ I have had my TiVo Desktop software crashed so my PC was unable to communicate with the TiVo unit because it removed the server. These programs always alert about anything that can access the internet even if the is a perfectly legitimate reason for doing so. It can be quite tedious picking and selecting throught them and excluding them.

    I also experimented before with trial versions of these utilities where i would run one and it showed no errors and then I could run another and get thousands of errors.

    I think the ones that advertise on TV, especially the “Does your email take more than 3 seconds to download?” are exceptionally deceptive. That email statement alone has so many variables that have nothing to do with anything wrong with a computer or the presence of malware it is an alarm by itself.

  9. I am a computer tech and I have seen more customers get convinced by either advertising or on the advice of “tech” experts around the web. Most are overkill at best and harmful at worst. One customer had installed ten of these on his system and it took around 30 minutes to get the PC to boot.


    As the article outlines, I don’t recommend any. I recommend only addressing problems your experiencing, and then with tools specifically for that problem.

  11. I ran the ” free” registry cleaner scan that was offered on your own blog. I realize that you do not necessarily endorse your advertiser but in this case I figured that you would not allow an advertiser to cause harm. I was wrong. I did not fall for their offer but from then on I could not boot up my computer without first having to delete their ad to buy their registry cleaner. This went on for months and months until I was able to delete their software out of my computer. I will never open a “free” sample again. That site was Uniblue.

  12. I use CCleaner because it works for remove of junk files, temps, and history. CCleaner is not over active as in other ultility cleaners. I use other tools in CCleaner but tell my end users to just use the top two items.

    As for bad system cleaners, I have removed over 100 cases of this scam. The police have shut down most cases of this scam by stopping money flow. Scam artist are in jail now. Number of cases now have drop to null.

  13. Car dealers will try and upsell you with maintenance you don’t need, under the guise of “We know what is best for your vehicle.” Most products you buy, you’ve got the manufacturer or dealer telling you that you should use their brand of supplies to get the best results. Yet, I have not found Microsoft out there trying to push a registry cleaner/system checker/cleaner on us. If the people who made Windows don’t think that it’s important enough to come up with a piece of software to maintain Windows, then it’s likely not that important that we do this kind of maintenance.

  14. Hi Leo. This might perhaps be totally irrelevant to the technical side of the things outlined in the article, but I would like to thank you for all your trully wonderful effort and job that you do in helping and educating people. I am an IT pro myself and have been visiting your website for over a decade now. I truly appreciate and respect you as an honest person and a human with integrity who always stands by the facts and the truth. Thank you Leo.
    Alex (London, UK).

  15. Have you noticed Leo a lot of these programs will find ‘errors’ on a BRAND NEW system? Which sort of proves how worthless they are. And the big antivirus companies are not above peddling these as add-ons too, also by frightening you into purchasing them. All a very poor show really.

  16. I used to use a registry cleaner called REGISTRY WIZARD that a computer repairman recommended to me. It didn’t help much and would always break one thing in MS Office, which I would have to go back and repair. Another product that I used at one time trashed my registry once and I had to rebuild the computer; it may have been a program I still use called JV16 POWER TOOLS. I don’t use the registry cleaner it has, but it has a lot of other tools that are useful. SuperAntiSpyware does a good job of removing cookies and I run that often; it never has given me any problem. It always wants to remove one program that I need, but at least it asks first. Cookies generally aren’t harmful, but do tend to clutter up things. If the registry gets so bad that it causes problems on your computer, it is probably time to refresh and rebuild the computer anyway. I no longer believe in registry cleaners as they are of minimal value and are mostly unnecessary. Never found CCleaner to be of much benefit, which a lot of people seem to like; maybe the paid version is much better than the free version?

  17. Even your ‘free’ anti-malware scanners use scareware to try and convince you to get the paid version. The two in question I know of (and won’t name to avoid being scandalous) tell you at the end of the scan all of the ‘problems’ you have and can ‘cure’ with the paid version. One of these is startup programs that supposedly cause longer times (starting up of course) but the average Joe seems to think that this is about slowing the computer all the time, not the time they take to simply LOAD at bootup. This was confusing so many people on Microsoft Answers that it took forever to explain it to them and calm them down and no, they were fine with Free, hit skip and ignore everytime. ‘Putting the apps/programs to sleep’ only sounds like it takes longer to start them up once you do need them and then how did they know what they really needed to have running at startup anyway? Your computer executes at least 2 billion instructions per second, per processor in the case of multiple cores, which are the rule these days, so it’s not the least put out.

    And I still use this scanner after ten years anyhow, even if the company that owns them now has jumped the shark on this.

    Windows itself is perfectly good at cleaning itself up and those obsolete files will be removed from the registry and eventually written over either when your app is updated or you uninstall anyway. You don’t have to make your digital bed and clean your virtual room. Much has changed and improved since the original responses from 2011.

  18. @David Hutchins, since I can’t seem to make the reply link work today…

    You don’t have to reload or ‘rebuild’ all the time, your OS/browser/etc are fairly robust, unless you need a hard drive replacement or penicillin for that computer.

    You can remove cookies yourself, without an app, you can even set your browser so that it doesn’t accept them (but then nothing much works) or clear them each time you close your browser. Cookies are not bad. They are instructions that your browser saves to go back to that site or page without having to completely look it up and find it from scratch. Again, nobody sent them to your computer…it created them itself from the site data it loaded the first time.

    If you need to you can always clear them out at start over. Easy as pi, to at least 5 places.

  19. I realize that to the cognoscenti registry cleaners are generally regarded as “snake oil”, and I indeed tried one once which did “break” my system.
    On the other side, though, I have used TuneUp since 2002 with, I believe, some good results and no bad ones, apart from the later versions introducing a new service I would rather not have. It’s a relatively conservative program. The last time I ran One-Click Maintenance it reported that it had corrected 425 “problems” in the registry, probably mostly entries left behind by uninstalled programs.
    One proof for me that these programs can work is that some years ago on my XP system the Event Viewer reported this serious error at each start-up:
    “Event ID: 1502 Source: Userenv
    Description: Windows cannot load the locally stored profile. Possible causes of this error include insufficient security rights or a corrupt local profile. If this problem persists, contact your network administrator”.
    I researched the error, and found that the profile is stored in the Ntuser.dat file. I tried various suggestions to no avail and was left with unappealing prospect of re-installing Windows and losing all of my large collection of programs.
    I then came across a small, old, free program called NT Registry Optimizer and thought I’d give it a try in the hope that it might repair the file. To my amazement, after running it, the Ntuser.dat file was reduced in size by a third, and the error never came back.
    I would like to know whether later versions of Windows have better built-in facilities for dealing with problems of this kind than XP so that such problems are less likely to arise.

  20. Just to answer my own question, I did a search and came across this article about how Microsoft’s own view of registry cleaners has changed over the years:
    It seems that in the past MS not only endorsed the use of registry cleaners, but even produced its own. With XP, it became more equivocal, but still included a registry cleaner in Windows Live OneCare and in its Safety Scanner, which continues to be offered as a fully maintained malware remover. In more recent years (since 2011 for Live OneCare) these have been withdrawn. Apparently since “Windows Vista the Registry has been Virtualized and … does not tend to suffer from bloat. Due to Virtualization, applications are prevented from writing to System Folders and to the ‘machine wide keys’ in the registry”.
    This would certainly seem to reduce, if not eliminate, any justification for using such cleaners in the later systems.


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