A registry cleaner optimizer performs one or more functions involving the Windows registry. This is a database of information about the various programs on a computer. Cleaning the registry can theoretically lead to performance improvements. There is some debate about how successful such tools are, or whether they may even do more harm than good.
In almost every case, a registry cleaner optimizer will be designed for Microsoft Windows. Within this operating system, a tool known as the Windows Registry acts as a database for configuration settings. This covers Windows itself, applications from both Microsoft and third-party developers, and the driver files that allow hardware devices to interact smoothly with the operating system.
The reason many users find a registry cleaner optimizer useful is that the registry will often, over time, become outdated and inaccurate. This usually happens when users install and later uninstall software. In theory this uninstallation should be a smooth process that leaves no trace of the software ever having been on the computer. In practice, many developers do a poor job on this element of their applications and do not set them to, in effect, clean up properly before leaving. The result is that the registry can become clogged up with entries that refer to files that no longer exist. This can cause Windows to either slow down or even malfunction when it tries to follow these entries.
The main activity of a registry cleaner optimizer is to hunt through the registry looking for outdated entries. It can then either update the entry to point to the correct location, or delete the entry altogether. It is theoretically possible to do this manually, but most people will find an automated process much easier.
The other main task offered by a registry cleaner optimizer is to optimize, or defragment, the registry. This effectively means removing physical gaps that have appeared in the registry after files have been deleted. In turn, this means the registry becomes smaller and it takes the computer less time to access the relevant entry. This is the same process as used in hard drive defragmentation, though as the registry is much smaller, the effects may be less drastic.
Whether it is necessary to use a registry cleaner optimizer is a disputed issue. While some people argue that they do make a notable difference, others argue that any improvement will be barely visible, and that there is a risk a valid entry could be deleted, thus actually worsening the problem. With this in mind, users may prefer to use cleaner tools that include a simple but comprehensive back-up feature, making it easy to undo any changes that turn out to cause problems.