The Windows Registry's job is to keep an eye on everything Windows does, and most of the time it does that perfectly well. From time to time, though, something throws a spanner in the works. Crashes, application updates and uninstallers can occasionally make a mess of things.

Registry cleaners can help by cleaning up those kinds of messes, and while the claims of some manufacturers are ridiculously overblown – registry cleaning isn't something you need to do unless you suspect there's a registry problem, and fixing flaws won't suddenly turbo-charge your PC, improve your memory or make your hair more glossy – the reputable ones are pretty good problem-solvers. These are our favourites.

AML Free Registry Cleaner

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AML Free
AML: ugly, but does the job beautifully

It's not the prettiest program you'll ever see, but the ALM Free Registry Cleaner is a useful tool. Its Startup Manager enables you to see what's being loaded when Windows boots and disable anything you don't want. It can help find and erase unnecessary files, and its registry search zips through even the most bloated Registry at high speed.

Auslogics Registry Cleaner

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Auslogics
Create a snapshot of your Registry for safe rollback

Registry cleaning isn't always trouble-free, and if you don't know what you're doing it's possible to do something horrible to your system. Auslogics Registry Cleaner has the answer to that: it creates a snapshot of the registry before making any changes, so if everything goes south you can roll back to undo any changes.

Unlike many cleaners, which present you with a huge list of results without any indication of how severe or otherwise the errors might be, Auslogics' app provides a rating that differentiates between problems that really don't matter and problems that really do.

CCleaner

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CCleaner
The ultimate all-round PC cleaning tool

CCleaner is a good all-round PC cleaning tool, and its registry features are particularly well thought out: a number of tickboxes enable you to choose exactly what CCleaner should be looking for, so for example you can scan for unnecessary help files, programs that launch at startup, problems with applications and so on.

The app creates a backup before making any changes, and it's extraordinarily quick. Best of all it's updated very regularly, so it's happy with the most recent Windows versions and updates. If you're considering a registry editor or system optimiser, this is the one we'd look at first.

EasyCleaner

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EasyCleaner
EasyCleaner works on pretty much any Windows OS

EasyCleaner wants to work on any Windows machine, and by any we really do mean any: the minimum system requirement is a 486 processor and it works on Windows systems going back to Windows 95.

It whizzes through the registry looking for out of date and invalid entries, and it also performs system maintenance tasks such as freeing up disk space, editing Windows' add/remove software listings and showing hard disk usage.

JetClean

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JetClean
Another nifty all-round system cleaning utility

Like CCleaner, JetClean is designed to do more than just find and fix problematic registry entries. It promises a 1-click PC cleanup by repairing the registry, removing unnecessary files, rearranging files on the hard disk and removing temporary files, recent file lists and other cruft.

There's also a portable version that you can run from a USB drive. Unusually, you can't just download the portable version: you have to generate it from inside the app.

Offline NT Password and Registry Editor

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A bit of a niche one, this: as the name suggests, Offline NT Password and Registry Editor is about editing the registry to change passwords. It takes a bit of fiddling and runs in text mode, but the results are worthwhile as it can reset Windows passwords to let you back into a locked computer. It can perform other registry edits too, but for everyday edits it's a little too old-school.

RegCleaner

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RegCleaner
One of the very first Windows Registry cleaners

RegCleaner was one of the very first Windows registry cleaners, and while we'd quibble with developer Jouni Vuorio's claim that it's "fun to use", it is a simple and effective way to find and fix registry problems. The freeware RegCleaner became shareware in 2003 as part of the Jv16 Power Tools package, and while that one's still widely available to download, the most recent version is nicer and safer than its free predecessor. The trial period is a perfectly decent 60 days.

Wise Registry Cleaner

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Wise Cleaner
Regularly schedule Registry scans with Wise Cleaner

Wise Registry Cleaner has an interesting approach to getting paid: the program is free but if you want technical support, you pay for it (albeit not much: a year of email help is $9.90 and covers all the firm's freeware).

The program includes a scheduler that you can use to run registry scans automatically, and in addition to removing obsolete, temporary, invalid or redundant items from the registry it also includes some PC optimisation features that promise to speed up your PC. It's particularly good at warning you about potentially dangerous changes and it runs very quickly.