Registry Cleaners FAQ

Frequently asked questions about registry cleaning & cleaner tools

Our free registry cleaner list is one of the more popular software lists on Lifewire. With so many scam registry tools out there, no wonder so many look for a true freeware program to solve their Windows Registry woes.

But are there really problems that build up in the registry that need fixing? Are registry cleaners the solution to most of my computer issues? What does a registry cleaner actually do?

The short answer is no, there are few real "registry problems" that a registry cleaner/repair/fix-it tool can actually solve.

So why are there so many of these programs?! They do have a purpose, but few actually have anything to do with the registry anymore.

Confused? Understandable. Here are some much more thorough answers to some of the more frequent questions we get about these ubiquitous tools...

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What does a registry cleaner do?

A registry cleaner is a software program that scans the Windows Registry for entries that once had a purpose but, for at least one of several reasons, no longer needs to be there.

Once found, the registry cleaner presents those entries to you on the screen, will sometimes rank them by importance, and then suggests that you allow the program to automatically remove some or all of them from the registry.

While that might sound pretty straightforward, which it is, what makes one registry cleaner different from another is how well a program does this task, as well as what entries, called registry keys, a program has predetermined is bad or unnecessary.

The Windows Registry doesn't get "dirty" and thus need cleaning. Registry cleaners do, however, do a great job at fixing certain kinds of problems.

Here are some examples from the popular CCleaner tool:

  • Missing shared DLLs
  • Unused file extensions
  • Type libraries
  • Applications
  • Fonts
  • Application paths
  • Help files
  • Installer
  • Obsolete software
  • Run at startup
  • Start menu ordering
  • Sound events
  • Windows services

CCleaner lets you pick which of those categories that you want the program to scan. For example, if you scan for registry issues related to obsolete software, the program will look for software that has been removed from your computer but that still has entries in the registry.

Or maybe the registry cleaner you're using will find redundant or empty entries in the Windows Registry, in which case deleting those items will provide the benefit of better organization.

Menu ordering is another common area of Windows that a registry cleaner will scan. What this does is deletes any customizations you've made to certain menus, effectively resetting them back to the way they were before you made changes.

Beyond choosing what to look for, a registry cleaner usually also gives you an opportunity to pick what should be deleted from the results, plus whether you want to back up the registry first. After a scan, the registry cleaner might provide a summary of what was cleaned and may even give you an "estimate" of the free space or performance improvements you can expect from the cleanup.

Some registry cleaners are really multipurpose tools that can do a lot more than just clean up registry items. They might also defrag the hard drive, delete temporary filesremove browser caches, and more.

How often should I run a registry cleaner?

You absolutely, positively, do NOT have to run a registry cleaner on any kind of regular basis!

In fact, most computer users never have a legitimate reason to run a registry cleaner. A lot of people are surprised to hear this as our answer, but it's true.

Contrary to the online advertising pitches, the bad information from your neighbor, and perhaps your own belief prior to this moment, registry cleaning is NOT a computer maintenance task. We can not be more clear on this topic.

A long time ago, registry cleaners were more often, and more correctly, referred to as registry repair programs because that's what they do — they repair certain kinds of issues in the Windows Registry that cause a very short list of computer problems.

Habits are hard to break, though, so we often get this follow-up question at this point:

Maybe registry cleaning is overrated, but what's the harm in running one every day/week/month/year... just in case?

Honestly, we'd go beyond overrated and say unnecessary. Why would you want to do any kind of maintenance that's completely unnecessary?

Do you clean your smartphone screen with borax even though a bit of water and a microfiber cloth does the job? Do you soak your favorite book in soapy water to get the dust off when a quick wipe accomplishes the same thing?

Analogies are helpful, but let's get to the specifics with regards to registry cleaning:

For one, it's a waste of your time. You have work to do, viral videos to watch, fantasy football leagues to plan, etc. Whatever else you like to you use your computer for is a better use of your time than running a registry cleaner for no particular reason.

Secondly, it's a waste of your computer's resources. Using your computer's hard driveRAM, and CPU for legitimate purposes is why you have a computer in the first place, but there's no reason to wear out those pieces of hardware even minutes sooner than need be with registry cleaning.

Finally, and most importantly, letting an automated tool mess around with one of the most sensitive areas of Windows.

Don't get us wrong. As we mentioned in the first section above, there's a time and place for registry cleaners, but it's certainly not a regular computer task anyone needs to do.

Yes, running a defrag program is a great thing to do every so often because files get fragmented over time, but it's absolutely not the same with "errors" in the Windows Registry.

What types of computer problems do registry cleaners fix?

The only real computer "problem" that registry cleaner programs are good at solving are error messages about missing files, especially those that appear as Windows starts up but are easy to clear with an OK or Cancel click.

Those "missing file" errors often appear because the Windows Registry references a file that it can't find on your computer. There are two common causes for that situation: malware that was incompletely removed or uninstallation routines that don't finish properly.

Incompletely removed malware isn't anything to be concerned about. Your antivirus program no doubt took care of the executable(s) causing the actual infection, meaning the virus, worm, or other malicious software can no longer do any damage. What's left in the registry is just a "leftover" of sorts, like a bit of harmless evidence after a crime.

It's a similar situation with botched software uninstalls. Maybe you didn't let a program's uninstallation process finish, maybe the software's programmers didn't code the uninstall process properly, or maybe you tried to manually remove a program instead of following its proper uninstall process. Any of these situations can lead to registry keys that mention files that aren't around anymore.

A registry cleaner, being a specialized tool to find just these sorts of "useless" keys, is one part of an arsenal of troubleshooting steps at your disposal. However, even in those cases, using a registry cleaner is just one of many useful troubleshooting steps to try and sometimes isn't the thing that ends up fixing the problem. For example, with an uninstall process that isn't/didn't work correctly, a better tool is an uninstaller utility.

We also highly recommend searching for the specific error message you're getting using the search box at the top of this page and, if we have a troubleshooting guide for that error, following that.

If registry cleaners only fix a short list of problems, why then are there so many registry cleaner programs made and then aggressively advertised to convince you that they're valuable tools to fix a long list of computer problems?

As with many things in life, this boils down to money and old habits.

  • A registry cleaner will not fix a computer startup problem.
  • A registry cleaner will not fix a Blue Screen of Death.
  • And, ironically, a registry cleaner will not fix any issue that Windows actually reports as a registry issue, like registry corruption, a missing registry, etc.
  • Registry cleaning also does not speed up your computer, an often advertised benefit of using one of these programs.

If it sounds like we hate registry cleaners, we don't, we just don't want you to get the slightest impression that registry cleaning is a panacea for your computer's ills, a pervasive myth that seems hard to bust.

Interestingly, the most useful parts of modern registry cleaners are some of their features that have nothing to do with the registry at all.

Registry cleaners have morphed into overall "system cleaners" of sorts, removing not only the unused registry key here and there, but also MRU lists, temporary files, browser download histories, and more.

While those things don't need to be removed either, they do contain personal information and so are handy for erasing your private information from a computer.

Should I fix all the problems a registry cleaner finds?

Assuming you pick a good registry cleaner, like one of the top rated ones in our list of free ones, then yes, it's perfectly fine to take whatever actions are suggested by the program.

While it might seem like the registry cleaner found a huge list of problems, the few hundred or even few thousand entries it found are useless keys and probably an incredibly tiny fraction of the size of your entire registry.

Now, with all that said, please know that while most registry cleaners find a lot of "stuff" in the registry, it's highly unlikely that any of it is causing problems, certainly not serious ones.

That long list of issues that your registry cleaner shows you, and then impressively deletes in just a few seconds, are all registry keys that point to files or other items that are no longer on your computer, a fact that does not necessarily indicate a problem.

In our test, we scanned a computer with CCleaner and it found 864 "issues" in the registry. Every single one has a category of issue assigned—ApplicationsSound EventsHelp filesInstaller, etc. Some other ones sound pretty ominous, like Missing Shared DLLs, or ActiveX and Class Issues.

ActiveX and Class Issues, especially, sounds pretty bad. In fact, it's the only category in CCleaner (and yes, we're picking on CCleaner—sorry!) that uses the word "issues" in its description. However, this "issue" like all the others in the list in this tool, and others, are referring to registry keys that exist that don't do anything.

Let's repeat that: the issues refer to keys that don't do anything. If they don't do anything, then they don't do anything—good or bad. In other words, none of these things are issues, nor are they keeping anything working, so remove them, or don't...it doesn't matter.

In case it's not yet clear: if you aren't having any kind of computer problem right now, or you're running a registry cleaner on a regular basis, there's really no need. Save yourself some time and energy and just skip it altogether.

Will a registry cleaner speed up my computer?

No, a registry cleaner will not speed up your computer.

If there's no way that a registry cleaner tool can speed up your computer, why do so many registry cleaners, especially ones that you pay for, make this claim all over their advertisements and websites?

Quite frankly, they do so to sell or encourage the use of their software. Users of sluggish, aging computer systems spend millions of dollars every year on "fix it" programs, hoping to solve a sometimes complex and expensive problem with cheap and easy-to-use software.

Some registry cleaner software makers will go a bit further and attempt to explain this magic ability in their programs by asserting that cleaning out the registry will result in a smaller registry. While that may be true to some extent (more on this a bit later), implying that a smaller registry means a faster Microsoft Windows is simply unfounded.

While a drastic decrease in registry size could have a minor impact on how fast Windows does certain things, the small amount of unnecessary data a registry cleaner will remove has but an ultra-small impact on your registry's size.

On an old, Windows 8 test computer, we exported the entirety of the Windows Registry, which came in at 409,980,298 bytes (around 410 MB). It contained 468,902 individual registry keys.

We then ran the registry cleaning portion of CCleaner on this computer, which had never had this, nor any, registry cleaner ever run on it before during its 2 years of heavy use.

CCleaner found and removed 329 unnecessary registry keys, totaling 82 bytes in size.

The math here is pretty clear: CCleaner found that just 0.07 percent of the keys in the registry were unnecessary, and removing them shrunk the size of the Windows Registry by just 0.00002 percent.

That size difference isn't nearly enough to make a noticeable impact on system performance, but the lack of a registry cleaner's power to speed up your computer isn't the only thing to consider when choosing not to run one. There are only a few good reasons to at all.

When we say that a registry cleaner won't speed up your computer, we're saying that the specific registry cleaning functionality of a registry cleaner program will do little good at making your computer faster. There are, however, registry cleaners (like CCleaner) that include extra features unrelated to the Windows Registry, of which are usually very helpful at speeding up a computer.

Will a registry cleaner I pay for fix more problems than a free one?

We have yet to find a commercial registry cleaner that comes close to the features, safety, and speed of any of the top several freeware registry cleaners from our list linked above.

There are plenty of free registry cleaners and also just as many that ask for $10, $20, or more USD to get the job done. Does this make them better? Is the premium program digging deeper and finding new things to clean, or is it a waste of money?

Free vs Commercial Registry Cleaners

When we talk about free vs commercial software, this is the place in the conversation where we'd say something like "unless there's a feature that you're really after in the commercial tool" but frankly, registry cleaners only do one thing: find unnecessary registry keys and remove them.

The free ones do it as well as the commercial ones. There's not that much to it.

Granted, one registry cleaner may find more keys to remove than another, but that's hardly the judge of a good program in this category.

One argument we see from time to time is that commercial registry cleaners often include an "always on" feature, continually keeping your registry clean. While there are certainly advantages to having some tasks taken care of in the background, registry cleaning is not one of those tasks that needs constant attention.

In most cases, you get what you pay for. In the case of registry cleaners, however, it seems that free is best.

What About Extra Features?

Where the real value of a paid registry cleaner comes in is when the software is more of a suite with several other tools built in. The question, then, is not whether you're getting more for a paid registry cleaner but if the other tools included in the suite are worth the money.

For example, one free registry cleaner might simply have registry cleaning functions. If that's all that you're after, then downloading it is the end of the story. However, if you find a paid registry cleaner that also includes a RAM booster, disk cleaner, Windows Update utility, etc., then paying for it might make sense.

Advanced SystemCare Pro is a great example of this. It has a registry cleaner built-in but also a defrag utility, RAM cleaner, auto-care functionality, internet speed booster, spyware protection, email protection, and more. Paying for that program could make sense if you're after more than just the registry cleaner and you want it all neatly bundled within one download.

With that being said, there are almost always free alternatives. If you just want a registry cleaner, stick to the free ones we've handpicked in the list linked at the top of this page. If you want some other tools that can do more to make your computer faster and safer, then download those individually, but remember that most are free.

To reiterate...a paid registry cleaner is really only better than a free one if it also includes extra tools that you want on your computer. Specifically, tools that you can't get anywhere else. But since there are so many free programs out there, it'd be difficult not to find a free version of whatever it is you want in addition to your registry cleaner (e.g., there are free virus scanners, disk cleaners, and more).

Why is CCleaner asking me to pay?

CCleaner is absolutely, positively free, at least as of our latest review. There is a paid version, but you don't need it to use the registry cleaning function.

Remember that CCleaner is a lot more than a registry cleaner and so nearly all other aspects of the program are free to use completely as well. You can find a complete list of features at CCleaner's official website.

Why, then, is there so much confusion about CCleaner? Why do we get an email every week or so complaining that part or all of the program is asking for payment?

Unfortunately, one or more other not-so-free programs masquerade as CCleaner, oftentimes in large banner advertisements on some websites, tricking at least some people into downloading their program.

After finding lots of "problems" and maybe even infecting your computer with some malware, it demands that you pay-to-fix.

The poor victim then searches for more about CCleaner, finds us, and well, here we are.

To avoid this problem, make sure you're only downloading CCleaner directly from CCleaner's website, which is the "Builds" page. That's also the only page we link to in our review.

See our How to Safely Download & Install Software guide for some general information on how to make sure you get what you expect when you download programs.

Confusion About CCleaner Versions

Beyond that, there's also sometimes some confusion with the editions of CCleaner that Piriform (the company that makes CCleaner) offers.

For home users, Piriform offers CCleaner (the free version we've linked to already), as well as a Professional edition. The Pro version offers some optional extras and does cost money, but it's clearly labeled as such on their site.

Also, if you open the free version of CCleaner, you'll see some options that aren't actually usable unless you pay, but you don't have to if all you want is the registry cleaning functionality. For example, scheduled cleaning is only for Pro users but free users can still see the option in the program; it's just not usable.

Several commercial editions of CCleaner are also offered for business users but are also clearly labeled.

If you're using CCleaner as a registry cleaner, there's no need at all to use anything beyond the free version. There are no bonus registry cleaning features offered in any of the pay-for editions of CCleaner.

Are registry cleaners safe to use?

Most of the time, yes, letting a registry cleaner remove the registry keys it finds as problematic or useless is perfectly safe.

Back in the mid-1990s, around the Windows 95 days, we clearly remember more than one situation where a commonly used, but poorly developed, registry cleaner caused regular problems with computers. Some were rendered so useless from the registry cleaner that reinstalling the operating system was the only solution.

Fortunately, the quality of registry and system cleaners are significantly higher now. Most of these tools have built-in ways to reverse changes when things don't go as expected. Plus, like with almost all things on the internet, reviews and attention to quality have driven the best programs to the top of every list and the poor ones out of existence.

Of course, playgrounds today are safer than they were 30 years ago, but that doesn't mean that you should take your kids to the one right next to the county jail or an industrial chemical plant.

In other words, you have a lot of control over what happens. We don't mean picking and choosing through the hundreds of cryptic registry keys you're presented. We mean being diligent about your choices and taking proactive steps to protect yourself.

How to Know Which Registry Cleaner to Use

There are lots and lots of registry cleaners out there, some good and some not so good. Instead of using a trial and error method to find the best registry cleaner, or to find which one removes the most invalid or broken registry items, your best bet is to use a curated list.

Don't rely on whatever registry cleaner is paying the most for advertisements today or which ones the search engines are showing near the top this week. We've vetted them all already, so save yourself the time and energy and pick from a reviewed list.

CCleaner is definitely our favorite free registry cleaner but we also prefer using Wise Registry Cleaner and Auslogics Registry Cleaner above most of the others in that list. These specific registry cleaners tend to have the best features, are the easiest ones to use, and work the smoothest.

How to Protect Yourself From a Registry Cleaning Gone Wrong

Registry cleaners aren't perfect. Things sometimes go wrong during the cleaning process, and while this is especially true if you're using an outdated or poorly developed registry cleaner, it can, of course, happen to any registry cleaner, even the ones we've hand-picked.

Therefore, it's important to remember to back up the registry prior to letting a registry cleaner remove entries. Most registry cleaners do this automatically for you, so either make sure that's the case before deleting, or back up the registry yourself before getting started.

Backing up the registry is important so that even if the registry cleaner you're using doesn't have an undo option, you can always use that backed up REG file yourself to restore the registry back to the state it was before whatever bad thing happened.

Not All Registry Cleaners Are Virus-Free

Something else to remember is that unless you're using a registry cleaner from our list that's linked above—which we've verified are virus-free—there's a chance that the one you get elsewhere might have a virus or will install some other malware you don't want. A good antivirus program will catch stuff like that and prevent you from installing the program, or will at least alert you that you shouldn't install it.

However, if you'd rather not use one of the registry cleaners we recommend, there are, of course, plenty of other ones out there. Just make sure that whatever program you choose, you're scanning it with some sort of antivirus tool, even a web-based one, and that you're using a download website that's known to share safe files.

What causes registry errors?

The "errors" in the registry that a registry cleaner removes aren't really errors. The entries they find might be unnecessary or pointless, but they're not errors in and of themselves.

Sometimes a registry key that shouldn't be there will cause an error message, usually a "missing file" error, but those errors don't mention the registry in any way and aren't always due to a needless registry key.

Aside from minor problems like orphaned registry keys left over by software uninstallations, empty keys, unused values, and duplicate keys, there are some types of real registry errors. By real, we mean errors that indicate true problems with the Windows Registry portion of the Windows operating system.

These sorts of errors are so serious that sometimes they prevent Windows from starting properly. Some mention that Windows can't access the registry, that the registry is missing, or that the registry is corrupted, among others.

Registry cleaners are completely useless in situations like this, partly because a registry cleaner needs a working registry to do anything at all. In other words, if there's an error message on your computer about the entire registry having been deleted or that your computer can't open, export, or edit the registry, there's no need to install a registry cleaner.

What to Do About Real Registry Problems

Your best course of action when you have a true registry issue is to follow standard troubleshooting procedures. For example, maybe your computer won't start, in which case you can follow that link to learn what to do there. Or, if you're lucky and Windows will start, you can perform a System Restore.

The idea here is to address the specific problem at hand and not just go directly into a registry cleaner in hopes that it will solve all your problems. It's unlikely to do much at all to fix actual Windows Registry hiccups.

For example, there are some problems that cite the Windows Registry which might make you think you need a registry cleaner to "clean up the mess." In reality, they might not be related to the registry in that way at all.

REG files come to mind here, particularly when importing a REG file or exporting one. When you have problems doing these tasks, the Windows Registry is definitely mentioned because you're trying to do something within it.

However, with these errors, a registry cleaner is unhelpful because the problem lies elsewhere, like with how the REG file was built or with your permissions to access the registry. A registry cleaner attempting to clean up registry entries will have zero effect on your ability to work with REG files.

Another example is registry values themselves. You may have made some registry entries during a registry hack or tweak, but they don't work the way you intended them to. In this case, much like the ones we just mentioned, you need to address those entries specifically to see what has been mistyped or what isn't allowed, because throwing a registry cleaner at it will do no good.

Editing the registry remotely is another situation where you might see registry errors, but instead of looking for a fix with a registry cleaner, you might just need to enable the Remote Registry service, for example, or ask the remote user for their password.

Bottom line: be smart about downloading and installing software and clear your cache every so often and you probably don't ever need one of these tools.