Updated April 2014
Registry cleaners are software programs that remove unnecessary entries from the Windows Registry. Registry cleaners are especially useful for removing registry entries that point to files that no longer exist.
Note: I've only included freeware registry cleaner programs in this list - in other words, only completely free registry cleaners. Any registry cleaner program that charges a fee of any kind (e.g. shareware, trialware) will not be included here. If a free registry cleaner has started to charge and I haven't removed it yet, please let me know.
Important: Free registry cleaners should only be used to troubleshoot specific issues, NOT as part of your regular PC maintenance. See my Registry Cleaner FAQ for more about registry cleaning and registry cleaner software.
CCleaner is the best free registry cleaner program I've tested. It's easy to use, prompts you to backup the registry before it makes changes, and includes a number of other useful tools.
The CCleaner registry cleaner work on Windows 8 & 8.1, 7, Vista, XP, Server 2008/2003, and older Windows versions like 2000, NT, ME and 98. 64-bit Windows versions are also supported.
Piriform provides both installable and portable versions of their free registry cleaner.
If you're set on using an automated tool to fix an issue you have that's caused by a registry problem, I highly recommend you use Piriform's CCleaner freeware registry cleaner tool.
I tested CCleaner v4.12.4657 using both their portable and installable versions on a 64-bit version of Windows 8.1.
JetClean, a free registry cleaner by BlueSprig, isn't one I see mentioned a lot but I found it to be very well done.
The JetClean registry cleaner supports both 32-bit and 64-bit versions of Windows 8, Windows 7, Windows Vista, Windows XP, and Windows 2000.
JetClean scanned the entire registry in just a few seconds and has a well designed interface.
There are two major things I didn't like about JetClean. One: The number of cookies that JetClean considers keepable, by default, is a bit excessive. Two: It tries to install a toolbar, but you can decline it during installation.
I also don't like that there's not an easily available portable version of JetClean. Yes, one exists, but you have to "generate" one from within the installed version of JetClean on your computer. Strange!
I tested JetClean v1.5.0 in Windows 7.
Wise Registry Cleaner comes in very close to the other top rated registry fix tools. They've put together a fantastic free registry cleaner program.
Wise Registry Cleaner comes in both installable and portable versions and can be used on Windows 8, 7, Vista, and XP. 64-bit Windows versions are supported.
Some big pluses for Wise's free registry cleaner include fast registry scans, scheduled scans, and a clear separation between normal issues and those that are "unsafe," a feature I loved.
I don't like the fact that Wise Registry Cleaner pushes for a download of Wise Disk Cleaner at the end of the installation but it's easy to skip.
I tested the installable version of Wise Registry Cleaner v8.03 in Windows 8.
Note: I've linked to the download page for all of Wise Cleaner's products so scroll down until you find Wise Registry Cleaner.
Auslogics Registry Cleaner is another great registry cleaner program - it's probably one of the easiest registry cleaners to use out of all the tools I've tested.
Auslogics Registry Cleaner is compatible with Windows 8 and Windows 7 (64-bit and 32-bit), as well as 32-bit versions of Windows Vista and Windows XP.
My favorite feature of Auslogics Registry Cleaner is the colored severity rating for each category of registry area that the program finds that needs attention. This makes it really easy to figure out what might be having an impact on your computer.
If the several higher rated registry repair tools in my list don't give you the results you were looking for, give Auslogics Registry Cleaner a try.
I tested Auslogics Registry Cleaner v126.96.36.199 in Windows XP.
Note: Before downloading Auslogics Registry Cleaner, you may be asked to download other programs, but it's easy to deselect them if you wish not to install them.
AML Free Registry Cleaner wasn't part of this list when I first put it together which was an obvious oversight on my part. AML's free registry tool has been the most frequent reader-suggested addition to these programs.
The interface is a bit "old" in style, but AML Free Registry Cleaner makes up for that with a solid registry search, lots of still-free additional tools, and a long history of not accidentally causing more problems.
AML Free Registry Cleaner works on both 64-bit and 32-bit versions of Windows 8, 7, Vista, and XP, as well as on some Windows Server operating systems.
I tested AML Free Registry Cleaner v4.25 in Windows 7.
Glarysoft's Registry Repair is another good freeware registry cleaner. Registry Repair is pretty simple to use and is a good option if some of the better tools aren't working out for you.
Registry Repair works in Windows 7, Vista, XP, Server 2003, and older Windows operating systems like Windows 2000, NT, ME and 98.
I tested Glarysoft's Registry Repair v188.8.131.528 in Windows 7.
Note: After the installation of Registry Repair, you're asked if you'd like to run the program (this is typical) but you're also asked if you'd like to set "Glary Search" as your browser's homepage. Be sure to uncheck that if you're not interested.
I was pretty impressed with SlimCleaner Free. Aside from a standard registry cleaning abilities, there are lots of completely free extras with this program like software update checks, startup optimization, system cleaning, and a lot more.
Advanced SystemCare Free works in Windows 8, 7, Vista, and XP, and 2000. A quick look at the program's version history shows that it's updated pretty frequently, which is great.
I tested SlimCleaner Free v4.0.30878 in Windows 7.
Note: The download link I've included here is to CNET's Download.com. SlimCleaner does not host a copy of SimCleaner Free on their own site.
PowerTools Lite 2013 is a freeware registry cleaner created by Macecraft, makers of several popular Windows utilities. PowerTools Lite was fast and found a similar number of needless registry entries as other tools in this area of my list.
PowerTools Lite 2013 works with Windows 8, 7, Vista, and XP.
I tested PowerTools Lite 2013 v2.1.0 in Windows 7. No toolbars or other programs tried to install like with some other free registry cleaners.
Note: PowerTools Lite does ask for your email address but you can skip past it. If you do sign up, it's easy to unsubscribe the first time you get a message from them.
Kingsoft PC Doctor is another registry cleaner imbedded in a software suite.
This program is really easy to use, and the registry cleaner isn’t hidden away deep inside – it’s very easy to spot and run without any hassles.
One thing I didn’t like about Kingsoft PC Doctor is that you can’t schedule a registry cleaning at a later date, but you must instead run it manually. While this is the case, the manual scans do find a hefty amount of errors that are just a click away from being removed.
Kingsoft PC Doctor is said to work with Windows 7, Vista, and XP.
I tested Kingsoft PC Doctor v3.7 in Windows 8 without any issues.
EasyCleaner is one of the oldest and most trusted free registry cleaners out there. The interface is a bit dated but it's a solid registry repair tool.
The ToniArts website says that EasyCleaner works in Windows 7, Vista, XP, 2000, NT, ME, 98, and 95. Both installer and portable versions of this registry cleaner are available.
EasyCleaner took considerably longer than other registry cleaners to scan my registry but it did a fine job overall. I also liked how I wasn't asked to install a completely unrelated and useless browser toolbar during the install!
I tested the installable version of EasyCleaner v184.108.40.2060 in Windows 7.