What is the Windows Registry?
The Registry is a centralized, hierarchical database that stores all application settings in standardized form. The registry was introduced with Windows 3.1 and Windows NT, replacing the less advanced mechanism of INI files.
In addition to setting for high level user-installed applications and programs, the Registry contains settings for low level components and devices of the Windows Operating System (OS).
The Registry provides features that enhance the OS security and stability. Implemented as a database, it provides database-like features such as atomic updates, strong data typing and versioning and backup/restore services.
The Windows OS provides an API for the orderly access to the Registry.
What is Stored in the Windows Registry?
The Registry’s elementary components are Keys and Values. Keys are similar to folders, and can be nested within other Keys. Registry values are name/value pairs. Multiple Values can be stored under one Key, with the condition that each Value has a unique name and the value (of the name/value pair) has a predefined type selected from one of the standard registry value types.
The registry is split into “hives”, subsections of logically grouped Keys, pertaining to various aspects of the hardware and OS environment. For example, the subsection HKEY_LOCAL_MACHINE (HKLM) contains all the Keys pertaining to the local machine-specific configuration data and the subsection HKEY_CURRENT_USER contains all the Keys pertaining to the user-specific configuration data.
The sub-Key HKLM\SOFTWARE is the common section of the registry where user-installed applications will store their proprietary settings and configuration information, including the information required for licensing and un-installation of the application.
Why is it important to keep it clean?
The Registry is a centralized resource of the Windows OS. During the normal course of operations of a Windows PC, the Registry is constantly queried, manipulated, and altered by the OS itself and the applications installed and ran by the human user.
The perceived performance of the PC is closely tied to the “health” and size of the Registry. A perceived slowdown in speed and sometimes unexpected crashes may occur when the Registry gets clogged down with unnecessary historical information that is left stored in it. Improperly uninstalled programs, corrupt drivers, and orphaned tasks all contribute to the corruption of the Registry. It is a well-documented experience that the Registry’s size increases with the length of time the PC has been operated. Short of a total reinstallation of the OS, which can produce a dramatic performance effect, a periodical clean-up of the registry is recommended.
How is the Registry Cleaned?
The Windows OS provides a built-in tool for viewing, editing, and backup/restore of the Registry. The tool, the Registry Editor (regedit.exe) does not provide the information of what can be safely removed from the Registry, nor the safe procedure to perform the clean-up. Due to the sheer size and complexity of the Registry, a manual scan for extraneous and unnecessary information can be a daunting task.
Third-party tools and utilities provide this information and the means for performing safe maintenance on the Registry. The tools scan the registry for invalid entries and provide a list of the errors found. The user is then presented with the ability to authorize the proposed maintenance action. Some of the tools provide the user with the option of preceding the maintenance operation with a full registry backup.
Since there is no reliable way for a third-party tool to know whether a particular key is actually redundant, care should be exercised by the user when authorizing the maintenance procedures. Finally, some third-party registry cleaners served, in the past, as popular vehicles for the introduction of malware into the OS.
General guidelines for Registry Cleaners
In the choice of freeware, one must exercise caution and discernment. It is suggested to rely on publicly available and unbiased information, such as that presented by reputable online content providers, such PC Magazine (www.pcmag.com) and PC World (www.pcworld.com), or downloading sites such as www.download.cnet.com/windows/.
The following common sense, general recommendations apply when installing, configuring and operating Registry Cleaners. Due to the delicate nature of these tools and the Registry itself, it pays to pay attention carefully.
- Backup the Registry before running a Registry Cleaner
- Close all unnecessary running applications
- After the program proposes a fix to the registry, choose the “lightest”, least intrusive option first – you can always re-run the scan and choose a deeper clean later.
- Never choose an Auto Clean option. Ever! Always have the last approval decision on the proposed clean.
- When choosing the cleanings to accept, choose whatever “rings a bell” to you and sounds familiar. For example, if you have recently removed a piece of software and some garbage remains, this is a good candidate to choose.
- Take small steps. Test the operation of the PC and OS in between the cleaning steps.
- Once you approve a clean, let the program work uninterrupted until its completion. Do not operate the PC while the program is working.
- A monthly visit to the Registry Cleaner is a good preventative maintenance procedure.
Freeware Tools for Cleaning the Windows Registry
A good quality Registry Cleaner can be bought for up to USD$30. But the freeware tools have very good quality as well.
The following are 5 popular Freeware Registry Cleaners:
Tool Name: RegSeeker
Supported OS: Windows 2000/XP/Vista
Special Features: Cleaner with other Registry-related utilities.
Pay attention to: Avoid the Auto-Clean feature! No automatic restore (just double-click on the saved .REG file to invoke the built-in Windows Registry Editor Restore function).
Ease-of-Use: the program does not categorize the Registry errors or provides assistance in what needs to be deleted.
Download link: Download
Tool Name: Advanced SystemCare
Supported OS: Windows 2000/XP/Vista/ 7
Special Features: contains Spyware detector, PC optimizer and junk-file remover and Startup optimizer.
Pay attention to: attempts to automatically install the Yahoo Toolbar during the installation
Ease-of-Use: No built-in backup module, minimalist approach to the error presentation with no detailed information about the nature of the error or connection to open the Registry Editor in the Key. It is only recommended for advance users.
Download link: Download
Tool Name: Wise Registry Cleaner
Supported OS: All versions of Windows
Special Features: “safe-to-solve” and “not-safe-to-solve” categories, automatic backup feature are applied prior to any changes to the Registry.
Pay attention to: some entries that cannot be easily removed.
Ease-of-Use: not very user-friendly in eliminating the clutter, and access to backup and restore.
Download link: Download
Tool Name: Free CCleaner
Supported OS: all versions of Windows
Special Features: Internet Temp files, Application Cleaning, IE and Firefox cleaning, as well as Registry cleaning
Pay attention to: multiple runs might be required to clean thoroughly.
Ease-of-Use: category-based scrubbing, open entries for viewing in the Registry Editor, and exclusion list for false positives.
Download link: Download