Should I Clean My Windows Registry? (Why & Why Not?)

The Windows Registry (along with the Command Line prompt) is the scariest place for many people on their computers.

If you don’t know what you’re doing, we have always been told—stay out of the registry.

Yet there are many advertisements or online forums that claim cleaning your registry will improve the performance of your PC.

Who do you believe?

The registry has always been a mysterious part of the Windows operating system. If you are a Mac user, you don’t have to worry about it as OS X doesn’t use a registry system.

In this article, we will look at exactly what the registry is, how it works and if you should bother cleaning it—or not?

What Is The Registry?

The Windows registry is exactly what the name suggests—a central registry on your computer at its most basic level.

It holds everything your system needs to operate, including configuration files and user profiles.

The registry is a hierarchical database that contains application settings.

Registory Editor

In older versions of Windows, these used to be stored as text-based configuration files in each application folder.

Now (Windows 10) the registry acts as a central place to store all your application settings.

All the entries in the registry are called keys and subkeys which are then sorted into five major categories, referred to as hives.

In addition, the registry on a Windows PC stores your user passwords, device driver info, all your important Windows settings, and virtually everything else.

Storing everything in one central database means accessing the data is much quicker than looking for individual configuration files in separate folders.

Most of the registry is loaded into the RAM each time your system boots up, to give almost instant access.

For those of you who are more technically minded, the Microsoft library gives a detailed explanation of the Windows Registry, which can be found here.

Nearly everything you do on your Windows computer is recorded in your registry.

The URL of this article you are reading at the moment probably already has an entry somewhere, along with the last ten or so documents and images you have opened.

Any programs you have installed or even the ones you have removed will have details in there too.

Before even delving into the registry or considering cleaning it, it’s crucial you back it up.

Failure to do so will mean a full reinstallation of your operating system and a loss of all the data stored on your computer.

Check Also: 5 Tips for Curing Computer Cable Clutter

How Is the Registry Stored and How Do You Back it Up?

System Restore Points

We now know there is this huge database on our computer, but where is it?

Although the registry is supposed to be all consolidated in one place, it’s not actually stored in a single file.

All system files, apart from the “HKEY_CURRENT_USER” are placed in the “%SystemRoot%\System32\Config” folder while the rest are stored in the “%SystemRoot%\Profiles\Username” folder.

There are a great number of files for your system to store.

The best way of backing up your registry is to create a system restore point, as shown in the YouTube video below.

View the video here:


Many of the more popular backup packages that you can now buy will also include tools that should be able to back up or restore your registry.

Microsoft actually recommends a system restore or a manual backup for most users. To manually back up the registry, you need to use the registry editor or “regedit.exe,” which is provided in Windows.

Using The Registry Editor

One of the simplest ways of editing the registry is to use the regedit.exe utility.

You can either launch it from the “Start” menu or a run box by hitting “Win” + “R” then typing “regedit.exe,” before hitting “Enter”.

Once the editor opens up, you will see a tree-style view of the keys on the left of the window, with the corresponding values on the right.

The most important thing to remember when editing any of the registry keys is to export the selected key before making any changes.

Registry Export

It may not always be possible to change the value back to what it was.

You can also use regedit to connect and edit the registry of another computer if you have full administrator access and the “RemoteRegistry” service is enabled and running.

Even If your machine won’t boot up into Windows anymore, if you can get to the recovery console, there’s the option to use a reg.exe utility from within the command line.

What Is A . Reg File?

If you have ever looked at some of the websites which offer tweaks or hacks for Windows, you will have no doubt seen downloadable .reg files which someone has uploaded as a way of quickly changing or adding a setting to the registry.

All these files are just simple text files.

They provide instructions to the regedit.exe utility to add, remove or change, some of the keys in your registry, without the manual typos that may cause the system to crash.

Although applying a .reg file is generally safer than manually tweaking your registry, it’s recommended that you first open the file in a text editor like Notepad to see what it contains.

Also, make sure you only use .reg files from a trusted source. A faulty or malicious registry key can be worse than any virus you have ever encountered.

The Potential Problem With Your Registry

Reg File example

Old or “bad” keys are where problems may lie.

If you look into your registry, it will be as cluttered as your average teenager’s bedroom.

Windows don’t have an efficient registry cleaner itself.

The registry is constantly creating new entries but it leaves the old ones in there too, long after they are needed.

To make matters worse, many of the applications you use don’t remove all the registry entries they have created when you uninstall them.

Program updates or installers can also leave unneeded keys in the registry, which could eventually lead to a bloated registry and your system slowing down.

Should You Clean Your Registry?

You would assume yes, from what we have just looked at.

You wouldn’t let your teenage child keep their bedroom in that state for too long.

The big problem is that messing with your registry—especially if you do it wrong—can destroy your Windows operating system, causing much distress at the same time.

It will make sulky teenagers look easy to handle.

We can’t stress enough that—if something you do in the registry goes sideways—you will need to install your OS again. It’s that dangerous!

The truth of the matter is that many people get away with never cleaning or managing the registry and see no effect on the performance of their PC at all.

Practices like removing any bloatware, freeing up disk storage space, and stopping or removing any unused services can all be more effective in boosting your Windows performance.

And much safer too.

One of the largest myths about the registry is that reducing its size will improve your PC’s performance.

Cleaner Software

A scan with a program like CCleaner will often reveal a couple of hundred to maybe even a thousand “bad keys” on your system.

Considering your registry has hundreds of thousands of entries or keys in the hives, these “bad keys” are a mere drop in the ocean.

To use another analogy, it’s like clearing the trash from the cabin of your car and expecting it to go faster.

Cleaning your registry will have little–if any–tangible effect on your PC’s performance.

Registry Cleaning Programs

The internet is awash with advertisements for registry cleaning applications that claim to fix your PC’s performance by giving the registry a good clearout.

Customer testimonials will say these programs have fixed every problem on their PC, from Active X errors to Java errors.

An unofficial utility supplied by Microsoft called “regclean” a few years back gave even more validity to the idea of registry cleaning.

But do they work?

The only possible answer is, perhaps.

It’s a bit of a cop-out but—in reality—most of these cleaning programs are not worth running.

The more reputable products like CCleaner or Iolo System Mechanic won’t kill your PC but they rarely help too much either.

As we said earlier, removing 200 or so keys from hundreds of thousands is unlikely to yield any performance gains. (Both of these programs will also prompt you to back up your system before any “cleaning”. Always a worthwhile step.)

Iolo System mechanic

Registry cleaners will not fix any potential startup problems and they won’t fix the dreaded Blue Screen of Death.

Ironically a registry cleaner won’t even fix issues that Windows actually says are registry issues, including registry corruption or a missing registry file.

However, the main computer problem they are good at solving is error messages that involve missing files.

When Windows boots up, you may get many missing file errors. Much of the time, just clicking “OK” or “Cancel” is enough to resolve those issues.

Two common causes of missing files can be either malware that wasn’t completely removed by your virus checker or the uninstallation of an application that didn’t finish the procedure.

Partially removed malware isn’t normally something to worry about; a good antivirus program will usually remove the executable part of the virus.

This means the worm or virus can no longer cause any harm. It’s as if the virus has left some harmless evidence behind at the scene of the crime.

Software uninstalls that haven’t been allowed to finish, or were not coded properly by the programmers, may also leave behind registry keys. Sometimes, if you try manually removing a package without using the uninstall program, registry keys that refer to files that don’t exist anymore may remain.

Again, in most cases, these will be harmless and in the scheme of things, from the hundreds of thousands of keys in the registry, pretty insignificant too.

How To Clean Registry On Your Windows OS

Sometimes, a build-up of invalid entries in the registry can lead to a potential decrease in the performance of your PC.

If your system keeps generating error messages or certain programs are failing to function, it may result in your system crashing and being unstable.


There can be certain circumstances where you have tried installing a program that hasn’t worked very well and it doesn’t completely uninstall itself.

If you have tried everything else, then maybe you will want to clean your registry.

Just be warned that even the simplest of mistakes can result in a major system failure, due to the delicate nature of the registry.

Always make a backup copy of the registry before starting with any changes. This can be an extra “belt and braces” security step, as many of the registry cleaner programs automatically back up as a safety measure.

The simplest option for most people is to use a reputable cleaning tool, many of which are free. The best ones are designed to avoid any critical keys which the removal of could harm your system. You can find a list of the ten best registry cleaner products here.

Most registry cleaners are as simple to use as a virus checker, with one click for a system scan, followed by clicking to fix the issues found.

The following YouTube video shows how simple CCleaner can be to use.


Manually deleting registry keys normally only applies if you have installed a bad key manually. These custom keys and manually created keys will be missed by many of the cleaning utilities because they are not seen as invalid.

If you think a certain key you have added may be the root of your issues, then you can use the regedit.exe tool we looked at earlier.

Simply open the regedit.exe utility and manually navigate to the key you assume is the problem.

Back it up first, just in case, and then delete it as you would for any other file or folder.

Be super careful when doing this and only proceed if you are 100 percent sure the invalid key is causing your problem.

To Clean Or Not To Clean?

Registry Clean

The only people who will tell you that you regularly need to clean your registry are companies trying to sell you software.

Most users will never need to go anywhere near their registry, let alone edit it or clean it.

If you are a techno-geek who demands a clean registry with absolutely no “bad” keys, then using a more reputable cleaner package will normally result in minimal damage.

Just be aware that you really should know what you are doing before poking around inside your registry.

Even some of the best registry cleaner programs have been known to delete important registry values when they have been incorrectly identified.

Be prepared for a system restore if it all goes wrong.

Of course, many people will disagree.

However, if you have the first set of benchmark results that prove a registry cleaner has significantly improved your PC’s performance, then please let us know.

About the Author Marcus

Marcus has a graduate degree in computer engineering and has many years of experience in cutting-edge technology research and development in both startups and Fortune 500 corporations. In his free time, he enjoys RTS gaming.

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