The Windows Registry is "The configuration database in all 32-bit versions of Windows that contains settings for the hardware and software in the PC it is installed in," according to the TechEncyclopedia. That's actually a pretty good thumbnail description. Wikipedia has a somewhat more detailed definition, which starts this way:
In computing, the Windows registry is a database which stores settings and options for the operating system for Microsoft Windows 32-bit versions. It contains information and settings for all the hardware, software, users, and preferences of the PC. Whenever a user makes changes to "Control Panel" settings, or file associations, system policies, or installed software, the changes are reflected and stored in the registry....
In all versions of Windows, the Registry can accumulate obsolete and nonfunctioning entries. Older versions of Windows, in particular, were notorious for this, often ending up with Registries containing huge numbers of erroneous entries. This slowed computer operations; and could even lead to crashes.
This led to the creation of a number of third-party software utilities that purported to "clean" the Registry, finding and eliminating the extraneous, useless, or just plain bogus data stored there.
Even Microsoft eventually got into the act, producing a small, unofficial, unsupported tool called Regclean for the Win9x family of operating systems. Microsoft made several half-hearted attempts at improving Regclean over several years, but Windows ME was then in the works, and it's registry was different enough from the earlier Win9x family to require that Registry tools work differently; and Windows NT/2000/XP required wholly different software. Because of this, Microsoft quietly abandoned Regclean, never having officially released it as a supported product. (It's still around on various non-Microsoft Web sites, however.)
Today, third-party Registry cleaning tools abound, filling the gap that Microsoft left. And that's a good thing, because even though XP is much harder to crash than was Windows 9x, it still can benefit from some Registry cleaning. For example, when you upgrade a PC from Win98 to XP, the new operating system will carry along a boatload of Registry settings from the old setup, just in case they might be needed. While this helps ensure that the new setup will work, it also virtually guarantees that the new setup carries excess baggage from Day One.
A brief aside to prove the point: On a recent "House Call" (an on-site PC-diagnostic and repair session at a reader's place of business or home office), one reader had upgraded a major-brand PC from Win98 to XP. This reader had above-average PC skills, and had regularly backed up his system, defragged, and otherwise maintained it, including running Norton's "WinDoctor" and ToniArt's "EasyCleaner" to help maintain the registry. Despite all that, we found and were able to remove some 3,000 additional bogus entries in his Registry. That, and some other maintenance steps we took, cut his PC's boot times in half, and made the system perceptibly faster and more stable. The full House Call repair is a separate story we'll tell at another time, but the salient point today is that, even using two Registry tools, he still had some 3,000 needless entries bloating his Registry and bogging down his system.
Nonupgraded systems also can accumulate some unnecessary Registry bloat, too, especially as hardware is added or removed, and software is installed, uninstalled, and upgraded. The more dynamic your system use, the more likely that your Registry will eventually accumulate a nontrivial number of obsolete or otherwise bogus entries.
But what, exactly, constitutes a Registry error? It's not an easy question to answer, as this reader letter illustrates:
Fred: What are your thoughts on Registry Programs? I have run five different programs on the same computer, without making any of the recommended changes, and get the following results:
Registry Repair from Stomp -- 732 errors
Registry 1st Aid from Rose City -- 73 errors
Registry Mechanic from PC Tools -- 18 errors
Registry Medic from Iomatic -- 50 errors
Easy Cleaner from Toni Arts -- 36 errors
No, that's not an error; Stomp did return 732 errors. Best Regards, John
There are several reasons for the disparity in those error counts. First there's the matter of simple semantics: At one end of the spectrum, there are Registry errors that -- if not corrected -- may make a system unbootable or unstable, or that may cause some of your software to crash or to malfunction. But at the other end of the spectrum, there are trivial, transient Registry items that are intended for short-term use, that harm nothing when they go out of date, and that are ultimately self-correcting via normal Windows housecleaning. Naturally, counting these latter as "errors" drives up the count and lets a given piece of software generate impressive-looking stats; but removing those "errors" doesn't mean much in terms of a real benefit.
Then again, some Registry cleaners truly are more aggressive than others, digging deeper and looking in more places for more kinds of errors.
Put those factors together and you can begin to see why one tool might report 18 errors while another reports more than 700 on the same system.
But understanding the problem of error-reporting doesn't tell you what tool to use. So, to try to get a handle on all this, I decided to try 10 different Registry-cleaner utilities on a test system here. The system, running XP Pro, was removed from live service, and thus wasn't a purebred lab machine. Rather, it's an ordinary, real-life office PC containing a normal suite of productivity apps, Web browsers, E-mail, and so on. In fact, it's so standard, most of you, reading this now, could sit down at the test PC and quickly begin using it productively.
The system was fully up to date with all patches and updates for XP and the installed software, including antivirus and firewall utilities. The system had been set up and maintained well (see System Setup Secrets For Windows XP, Ten Ways To Make Windows XP Run Better, Ten More Ways To Make Windows XP Run Better, and Make Windows XP Self-Maintaining.)
However, no Registry-cleaner software had been used on the system, and so whatever errors and other debris had been accumulating in the Registry since the original installation of XP was still in there.
I made a disk "image" (a bit-for-bit exact copy of the hard drive's contents) and then tried the 10 different Registry cleaners on the test system, one at a time. First, I'd install and run one cleaner three times, with a reboot between each run. I'd make a note of the number of Registry errors the software found and fixed on each run.
After the third run, I'd restore the original saved disk image, returning the system to the same initial condition it was in before any tests. Then I'd install and test the next cleaning tool over three separate runs, with a reboot between each run.
Testing this way ensured that each cleaner faced exactly the same initial conditions on its first run, with the Registry in exactly the same initial state.
Doing immediate second and third runs with each cleaning tool was to see if any of the programs under test were fudging their numbers by over-reporting errors. For example, if a tool was really doing what it said it was, it would find and fix all the errors it could on the first run. Immediate subsequent runs should show essentially zero errors, because they all were fixed on the first run, right?
But if a tool still reports a significant number of errors on the second and third runs, you might wonder what was going on: Why couldn't the tool find and fix all the errors the first time? Is the tool introducing new errors as it runs? Is it fudging the numbers to make you think it's doing more than it really is? Is it reporting as "errors" some things that really aren't errors after all?
At the least, it seems to me that a good Registry cleaning tool should report a stable, repeatable, and very low number of errors on back-to-back repeated runs. To me, a tool that can't get the number of reported errors down to a stable, low minimum number on repeated runs either isn't fixing things right, or isn't analyzing them right in the first place. Your mileage may vary, but I tend to stay away from tools that act this way.
The Tools And How They Did
I'll provide more detail on the individual tools as we go along, but the list includes JV16 PowerTools version 18.104.22.168 (the last free version of this venerable tool, considered by many to be the best free Registry cleaner ever offered); JV16 PowerTools 2005 (the current, commercial version of the classic tool); Registry Mechanic from PCtools.com; ToniArt's EasyCleaner; StompSoft's Registry Repair; Rose City's Registry First Aid; Iomatic's RegistryMedic; EasyDesk's Registry Drill; RegistryFix's eponymous RegistryFix; and Registry Cleaner from CleanMyPC. In each case, I downloaded the latest available version of each tool just prior to testing.
There are, of course, many, many other Registry-cleaning tools available. My choice of 10 is not meant to be definitive, but rather merely representative of what's available in this class of tool. If you have additional information on other tools of this type, by all means tell us: Use the link at the end of this article to post your information in the associated discussion forum.
Now, let's see what they did:
My Choice, Then Yours From the above, I think that EasyCleaner is the best free tool currently available; and JV16 PowerTools 2005 is the current best commercial tool available.
Because JV16PowerTools offers a full, free, uncrippled trial version, you might want to try this approach: First download and run EasyCleaner. See what it does on your system. Next, download and run JV16 PowerTools 2005. See what additional cleaning it offers you, above and beyond what EasyCleaner did. If there seems to be enough extra cleaning to make it worthwhile, register your copy. If not, then stick with EasyCleaner -- but use the "donate" button to send the author at least a few bucks for his time and trouble.
As for the others, it's up to you. Perhaps your system is different enough from my informal test setup so that you get very different results from the above. Or perhaps you use other Registry cleaning software, not included among the 10 tools I tested. If so, please join the discussion and share your experiences!