Registry cleaner

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A registry cleaner is a type of software utility designed for the Microsoft Windows operating system whose purpose is to remove redundant or unwanted items from the Windows registry. However the necessity and usefullness of registry cleaners is a controversial topic, with experts not agreeing on their benefit. The problem is further clouded by the fact that malware is often being associated with utilities of this type.

Contents 1 Purpose 2 Advantages 3 Disadvantages 3.1 Registry damage 3.1.1 Malware threat 3.2 Marginal performance benefit 4 References

[edit] Purpose

Registry Cleaners attempt to remove data from the Windows Registry that is no longer in use or that is unwanted on the system. Such data may include information left by software that has not been uninstalled completely from the computer, information that is no longer of use, or settings required for the operation of malware. It is possible that these persistent items may interfere with performance or have other negative impacts.^{[citation needed]} A legitimate registry cleaner scans the registry, and attempts to pick out the unnecessary values in order to delete or repair them.

[edit] Advantages

Registry cleaners, or registry cleanup software, can in some cases improve the performance of computers by ridding the registry of redundant information.

Due to the sheer size and complexity of the registry database, manually cleaning up debris and invalid entries would be impractical, so registry cleaners are essentially tools that automate the process of looking for invalid entries, missing file references or broken links within the registry and resolving them. However, due the the actual size of the registry hive (usually totaling in the 500kb range), its performance impact is negligible, resulting in no additional programs being run on the system as the majority of keys hold application configuration data. Startup programs are however stored in the HKEY_CURRENT_USER/Software/Microsoft/Windows/Current Version/Run and HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/Current Version/Run keys as well as the "Start Up" Start menu folder for "All Users" and <user>.

In certain cases the correction of a invalid registry key can provide significant benefit.^{[citation needed]} For example, a registry entry indicating a program should be run at startup from a network path that no longer exists can delay startup by as long as the network protocol takes to timeout, often a full minute.^{[citation needed]} Most registry cleaners however make no distinction as to the severity of the errors, and many that do erroneously categorize errors as "critical" with little basis to support it.

Noted Windows architecture expert Mark Russinovich has concluded that registry cleaners will continue to have a role until most applications have moved to the .NET Framework platform that does not rely on the registry for application settings.^[1]

Some registry cleaners offer backup and restore functions that allow the user to revert changes made by the registry cleaner in case they are undesired. A Registry Cleaner may be useful for someone that adds or removes programs from their computer very often, however most organisations would rebuild a problem machine back to a known, good state rather than waste resources trying to repair a machine that is not working. Furthermore, professionals typically use virtual machines for scenarios such as testing or application packaging where programs need to be installed and uninstalled frequently.

[edit] Disadvantages

[edit] Registry damage

Most notably, critics say there is no reliable way for a third party program to know whether any particular key is invalid, redundant or neither. Poorly designed registry cleaners may not know for sure whether a key is still being used by Windows or what detrimental effects removing it may have. This has led to examples of registry cleaners causing loss of functionality and/or system instability.^[2][3][4]

[edit] Malware threat

The benefits of Registry cleaners have been used by a number of trojans applications to install malware, typically through social engineering attacks that use website popups. These rogue registry cleaners often exaggerate the problems on a PC and are often marketed with advertisements that falsely claim to have pre-analyzed your PC with warnings such as "Performance Scan Results: Bad. Click here to fix." Rogue registry cleaner "WinFixer" has been ranked as one of the most prevalent pieces of malware currently in circulation.^[5]

[edit] Marginal performance benefit

On Windows 9x computers, it is possible that a very large registry could slow down the computer's startup time. However this is far less of an issue with NT-based Operating Systems (including Windows XP and Vista) due to a different on-disk structure of the registry, improved memory management and indexing.^[6] Slowdown due to registry bloat is thus far less of an issue in modern versions of Windows. More importantly, however, the difference in speed due to the use of a registry cleaner is negligible: rarely do they remove more than a few kilobytes from the total size of the registry. In fact, technology journalist Ed Bott has claimed that no-one has ever successfully managed to measure any significant performance increase from the use of a registry cleaner.^[7] Any potential user of a registry cleaner must thus balance a probably negligible performance increase against the possibility of system instability. A safer and more measurable approach to Registry performance is to defragment the Registry files using a tool such as PageDefrag.^[8]

[edit] References