Updated May 2013
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, 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 v4.01.4093 using both their portable and installable versions on a 64-bit version of Windows 7.
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, has a well designed interface, and didn't try to push some unnecessary browser toolbar on me during installation.
There were twp things I didn't like about JetClean. One: It isn't available in a portable version. Two: The number of cookies that JetClean considers keepable, by default, is a bit excessive.
I tested JetClean v1.4.0 in Windows 7.
Wise Registry Cleaner comes in very close to the other top rated registry fix tools. ZhiQing Soft has put together a fantastic free registry cleaner program.
Wise Registry Cleaner comes in both installable and portable versions and can be used on Windows 7, all the way back through Windows 98. 64-bit Windows versions are supported.
Some big pluses for Wise's free registry cleaner include fast registry 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 during installation but it's easy to skip.
I tested the installable version of Wise Registry Cleaner v7.31.469 in Windows 7.
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 7.
Note: During installation, Auslogics Registry Cleaner tries to install a browser toolbar and make changes to your home page. Be sure to uncheck those options if you're not interested. Also, feel free to completely ignore this program's sneaky system status check up-selling feature after the registry cleaning is complete.
Advanced SystemCare Free from IObit is another excellent free registry cleaner program. Advanced SystemCare Free is very easy to use, has an excellent interface, and includes several other "system care" capabilities, including the ability to remove some malware, clean junk files, and more.
Advanced SystemCare Free works in Windows 8, 7, Vista, XP, and 2000. According to IObit, both 32-bit and 64-bit versions of Windows are supported.
I tested the registry fixing abilities of Advanced SystemCare Free v188.8.131.52 in Windows 7.
Note: Advanced SystemCare Free tries to install a custom browser toolbar during its setup but it's easy to decline if you so choose.
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 v184.108.40.2068 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.
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 v220.127.116.110 in Windows 7.
Comodo System Utilities is yet another good freeware registry cleaner program. It's simple to use and scanned the registry in a reasonable amount of time.
The Comodo System Utilities tool is designed for Windows 7, Vista, Server 2003, and XP. It works on both 32-bit and 64-bit versions of Windows.
I tested Comodo System Utilities v4.0.226743.26 in Windows 7. There are several other features in this "utility" but I only looked at the registry cleaning portion.
I'm usually a big fan of Comodo products and Comodo System Utilities delivered on my exceptions. I especially liked a seemingly tiny feature: the ability to automatically create a restore point prior to clearing the registry. That could really come in handy if you run into a problem post-cleaning.
Eusing Free Registry Cleaner is another free registry cleaner. I frequently see references to this particular registry cleaner on other "top" lists but I didn't find anything spectacular about it.
Eusing Software says that their free registry cleaner works on Windows 7, Vista, Server 2003, XP, 2000, NT, ME, 98, and 95. Portable and installable versions are available.
I tested the installable version of Eusing Free Registry Cleaner v2.8.1 in Windows 7.
Tip: Remember, a registry cleaner program is not a regular PC maintenance tool. Registry cleaners don't typically speed up your computer or provide any other day-to-day improvements to your PC. Registry cleaners should only be used to help solve specific kinds of problems.