The main reason to use a registry cleaner is not to free up space, but to increase the speed of your software. When you remove all of those invalid, incorrect, or no longer used entries, the computer does not need to go through all of those entries before it can reach the correct, valid, and currently used entries, therefore causing all of your programs to run quicker. How are all of those extraneous entries created in the first place?

The most common way that extraneous registry entries are created is through uninstalling software. When you install software, it creates an executable file (.exe) in your registry. The computer needs this executable file to execute the software.  When you uninstall that software, though the software is gone, the executable file for that software still exists in the registry, even if the software it executes no longer exists.

Another reason that extraneous registry entries can be created is through malware creating malicious entries. If you have malware installed on your computer, it will create malicious registry entries to try to get your registry to do what it wants it to do, instead of what it should be doing.

Extraneous registry entries can be caused by poorly written software programs.  When you install poorly written software programs to your computer, extraneous registry entries can be written. The software may create more entries than it actually needs to perform. Extraneous entries can also be caused by errors in software programs, or errors in compatibility. For example, you might have a great software program that is trying to interact with a software program that it is incompatible with. This will create extraneous registry entries.

Lastly, extraneous registry entries can also be caused by a corrupted or damaged registry. In this case, the registry itself is creating extraneous entries. As you can see, extraneous registry entries are quite common, and can be caused by a variety of reasons. While these entries do not take up a lot of space, they do slow down your computer, and while cleaning the registry does not free up a lot of space, it does increase the speed of all of your computer’s software applications.