How do registry cleaners work

I also belong to the crowd and have CCleaner on my PC. So I decided to figure out what real value of registry cleaners is and whether we really need them in our modern operating systems. Registry cleaner is a category of open-source and proprietory software for the Windows OS, which aim is to remove items believed to be redundant from the Windows registry. Still this is a necessary component of any Windows OS, a database where Windows stores configuration settings for device drivers, applications, system services, desktop, and user interface.

It looks like this:. First introduced in Windows 3. However, already in Windows XP release, almost every application was utilizing it. With that much use, the registry soon became a bottleneck for PC performance.

Add here moderate hardware possibilities and little hard disc drive capacity. All this almost choked up computers in the early s. Numerous utilities promising to speed up computers via a simple deletion of unused registry information appeared and strongly occupied positions on software market. Why is it so? I often run the software to clean the items listed above. Here are some examples from the popular CCleaner tool:. 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 files , remove browser caches , and more.

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:. 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 drive , RAM , 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.

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. 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. 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.

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 "issues" in the registry.

Every single one has a category of issue assigned— Applications , Sound Events , Help files , Installer , etc. 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! 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 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.

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 ,, bytes around MB. It contained , 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 unnecessary registry keys, totaling 82 bytes in size. The math here is pretty clear: CCleaner found that just 0.

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. The Windows Registry is a large database that stores all kinds of information for both Windows and installed software. Every time you install or remove software or make changes to Windows settings, the registry is updated to reflect these.

You can edit the registry yourself using the Registry Editor tool. This is the only way to make a lot of advanced tweaks in Windows, since the settings they control aren't accessible anywhere else. See our introduction to the Windows Registry to learn more. When you see ads for registry cleaners or visit their websites, they'll make bold claims about their usefulness to your PC.

One cleaner, for example, says that it will "clean, repair, and optimize your Windows registry to eliminate errors and crashes, and to restore smooth and stable operation. They'll also tell you that "the registry can become littered with old entries", which will "cause error messages and slow the computer down.

Most of the time, these tools let you "fix" a few "problems" for free, then ask you to pay for a premium license to "fix" everything. In reality, what registry cleaners claim are serious issues are not problems at all.

It's true that uninstalling software can leave registry entries behind, or there could be unused file extensions that still have registry keys. However, these almost never cause Windows to slow down or throw error messages. Even hundreds of orphaned entries won't amount to anything more than a tiny amount of data on your PC. Thus, cleaning the registry will not have any noticeable positive effect on performance.

However, running a registry cleaner could actually cause damage to your system. While running a registry cleaner is useless at best, it's dangerous at worst. As mentioned, the registry is home to lots of important values that both Windows and third-party programs use.

If you delete, move, or damage these keys, critical system functions could fail to work. Since registry cleaners are automated, there's a good chance that their registry scan could tag something as unnecessary when it's actually important. And unless you're a registry expert and check every entry before deleting them, you could cause major damage to your system by deleting something inadvertently.

Deleting important registry keys could cause some software to stop working, requiring you to reinstall it. Corrupting important keys might introduce error messages when you try to use certain Windows functions. In the worst cases, doing this might even screw up your system and require you to reinstall Windows.