This is a common question in the computer repair trade because many software utilities (especially ones you have to pay for!) claim all sorts of wonderful sounding benefits from cleaning the registry.
The Windows registry is an important database storing thousands of configuration options and settings that Windows relies upon to run. It is backed up automatically by System Restore (see Create a System Restore Point) which can hopefully restore it (if it becomes damaged or parts are deleted by mistake).
Does It Need Cleaning? It is true that the registry grows in size as you install more programs – theoretically making it slower for Windows to access. Also, some entries within it may become obsolete when programs are uninstalled and other entries may point to the wrong place if programs are moved around.
Registry cleaning utilities claim to remove these redundant entries and to correct invalid entries. In theory then, cleaning the registry should fix the ‘errors’ and make the registry smaller, thereby speeding up your computer a bit.
What Are The Risks? In practice, very high. The registry database is extremely complex and it may not be possible for a cleaner to determine with 100% accuracy which entries should be modified. If the wrong changes are made to the registry some of your software programs may not work or your computer may not even boot up into Windows!
For these reasons we do not recommend registry cleaners as a means of trying to speed up a computer because it is impossible to tell with any confidence whether the changes they make will be useful or potentially damaging. If your computer is slow, see our article how to speed up a slow computer which provides safe steps you can take to improve speed.
What Do Microsoft Say About It? Microsoft used to offer a ‘Windows Installer Cleanup’ utility program which aimed to clean the registry of invalid program information but they stopped offering it for download because of problems it caused – it might help resolve some issues but at the same time it could damage other components installed on the computer…
We do not always agree with Microsoft but in this case we think their opinion is valid – the risk of damage far outweighs the possible damage caused by a cleaner. It is also worth noting that modern computers are so fast that invalid or obsolete entries in the registry are unlikely to cause any noticeable slowdown – it is far more likely that a slow computer suffers from one or more of the common problems discussed in our earlier article.
Magazine PC World ran a series of detailed tests that we have reviewed here on ‘speed booster’ utilities like registry cleaners and found that they failed to make any significant impact on computer performance – in fact on 1 of the 5 PCs tested all the programs decreased the computer’s performance!
Ccleaner was the best of the four programs tested – even though it is free. Whilst we love Ccleaner we would still only recommend it for experts cleaning the registry of specific items – not as a general purpose clean up tool to be run on a regular basis.