Registry cleaning is widely believed to be a key contributor to enhancing the performance of a computer.  What is your computer's "registry"?  It's a place that Microsoft Windows and all of the programs installed on your computer stores critical information for the proper functioning of your computer.  A messed up registry can result in a very confused or even completely disfunctional computer.  Changing the registry is a "proceed with caution / don't try this at home kids" operation.

Despite the dangers of messing with the registry, there are several registry cleaning tools freely available for download and use. Recently, my computer started to show all the symptoms of an aging machine in desperate need for a tune up. Though I am not a big fan of registry cleaning tools, I decided to download and run one of the freely available registry cleaning tools (the one with the most downloads) from a popular shareware site.

The tool provided a one click option to clean up junk as well as perform registry maintenance. A quick system scan summarized the amount of junk data piled up on my hard disk and highlighted the reason for my computer’s slow performance. With a single click I could get everything cleaned up and had my eyes set on registry cleaning options. The registry integrity scan presented a large number of invalid entries under different categories such as "Missing Shared DLLS", "Unused File Extensions", "Type Libraries", "Application paths", etc.

Since I've installed and removed numerous software packages over the years, I was won over by the authenticity of the scan results and decided to go ahead with the registry deletion recommendations made by the tool. The tool deleted the selected orphaned registry entries - what appeared to be a legitimate action to me.  I played around with other optimizations including a startup service review, disabled a few startup services and rebooted the system.

I soon found that I had signed up for trouble - trouble that ate up (and wasted) the rest of my day.  The first warning came up in the form of a Windows alert message box indicating a missing dll link during boot up. I ignored it and logged into the system. The system appeared to come up faster. Thinking that the tool had served its purpose, I launched Microsoft Outlook and realized that Outlook was no longer launching from the desktop shortcut.  I tried the start menu option but in vain. I tried launching the remote conferencing software from the desktop shortcut... only to get another pop-up error message.

It took me a while to figure out that some of the entries were knocked off by the registry cleaner, rendering half of my office productivity tools completely useless. I Google’d the web to see if there was any available fix but could not find anything specific except doing a complete System Restore to an earlier snapshot. I reluctantly fired up Windows System Restore and picked up the previous restore point in the hope that this will bring my system back to its original state. The Windows System Restore did live up to my expectations. A single reboot brought back the computer to its previous state, though with the existing performance sluggishness but with greater stability. However, the overall effort took away almost half of my productive day.

This may not be case with every registry scanner but it definitely raises questions about the integrity of registry cleaners available in the marketplace. The scan results definitely require a much closer look beyond a one-click fix solution to avoid any ad hoc deletes that can render your system instable. Some experts believe that a poorly authored registry scanner may cause more damage to your registry than any possible gain.  Also, malware / virus programs create entries inside the registry which are hard to detect and the removal of such keys can result in further infection.

Moral of the story  unless you have a technical understanding of Windows, it’s better to avoid using such tools and should be left to the experts to diagnose and fix slow computer problems.