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Welcome, Digg visitors. Wow, twice in three days an old post of mine gets picked up and Dugg like crazy. Just to be clear: If you have a specific problem with removing a specific program, a registry cleaning utility might be able to identify keys that will help you solve that specific problem. But that’s a rare scenario. Most people I know use registry cleaners as part of their magic cleanup routine, and I see very little upside and a lot of potential downside in this sort of routine use. Specifically, as I write below, I have never seen any evidence that routine “cleaning” of the registry has any positive effect. I stand behind that statement.

Via Matt Goyer, John Hoole offers this cautionary tale:

just a note to say if you have Windows XP Media Center Edition 2005 (probably all versions actually) steer clear of registry clean programs such as Reg Mechanic they go through your registry and delete unnecessary keys….. sounds good but it didn’t count on Media Center I ran it a few days back and when I came to use Media Center it loaded then produced a crash report and died, took me ages to figure it out until I came to run Reg Mechanic again and realized This program deletes DLL files too so….. I restored the first backup and rebooted and media center worked fine so if you have that error on startup that’s your problem right there. Just restore the backup from Reg Mechanic. So you have been warned.

I’d go a step further: Don’t run registry cleaner programs, period. I won’t go so far as to call them snake oil, but what possible performance benefits can you get from “cleaning up” unneeded registry entries and eliminating a few stray DLL files? Even in the best-case scenario the impact should be trivial at best. Maybe a second or two here and there, maybe a few kilobytes of freed-up RAM, and I’m being generous. How can you balance those against the risk that the utility will “clean” (in other words, delete) something you really need, causing a program or feature to fail?

If anyone has done any serious performance testing on this class of software, I’d be interested in seeing it. In the absence of really rigorous testing and fail-safe design, I say: Stay far away from this sort of utility.

If you have a counter-argument to make, leave a comment. But simply saying, “I use Reg-o-matic Deluxe and my computer is way faster than ever!” isn’t good enough. Show me the data!

Update: I did a Google search for “registry cleaner” performance tests, and got more than 25,000 hits. In the first 15 pages, however, there wasn’t a single example of an actual performance test. Virtually all the results were from companies that make and sell this sort of utility, or from download sites that have affiliate agreements with these developers. I found one recent how-to article from Ed Tittel on TechWeb. Ed asserts that “Most Windows experts recommend a Registry clean-up on all systems at least once every six months.” He didn’t link to any of those experts, however.

Later in the same article, Ed advises: “I urge you to check comparative reviews, ratings, and rankings of Registry Clean-up Tools before you invest hard-earned dollars on these products.” Sadly, there are no links here either. I suspect that’s because detailed comparative reviews of this class of software don’t exist. Ironically, the article inadvertently documents the case against this sort of utility. Early on, it states: “The typical Windows system has literally hundreds of thousands of Registry entries.” The screen shot from the free utility he spotlights shows a grand total of 19 “errors,” most of which are simply pointers to CLSIDs that don’t exist. Is it really worth spending hours on this task? I don’t think so.

The best bit of reading I found in my search was this rant from a poster named Jabarnut on a thread at DSL Reports’ Software Forum:

The Registry is an enormous database and all this “Cleaning” really doesn’t amount to much…I’ve said this before, but I liken it to “sweeping out one parking space in a parking lot the size of Montana” … a registry “tweak” here and there is desirable or even necessary sometimes, but random “cleaning”, especially for the novice, is inviting disaster.

I also would like someone to show me any hard evidence that registry cleaning actually improves performance. (Unless there is a specific problem that has to be addressed by making changes to the registry).

Sorry to go on like this, but I feel there is way to much Registry “Cleaning” going on these days just for the sake of “cleaning”.


Update 11-Sep: Several commenters have made a good case for a handful of utilities that include registry repair and cleaning options. They make the point that these are useful when used intelligently, not indiscriminately. My colleague George Ou from ZDNet passed along these comments:

I do like the free CCleaner. I’ve cleaned out 1 GB or more of junk on friends computers and it does make the system a little more responsive. You don’t get as many unexplained pauses. This is a problem with the lack of multithreading in Windows Explorer most of the time when it times out on dead resources like a detached network drive. I thought I remember reading something on the Vista features that fixes this by supporting multiple threads.

Other than that, I’ve made sure that I don’t have any dead links the system is trying to access on the desktop that are sure to cause a 30 second lockup even if I drag an icon across the dead link icon. Ccleaner also does a nice job removing a lot of that junk. The combination of MSCONFIG and Ccleaner works wonders.

OK, I’ll give it a try.

91 Responses to “Why I don’t use registry cleaners”

  • Janice says:

    Don’t…I’ve “experimented” with a variety of registry cleaners including ccleaner and though in most cases any damage could be reversed, in my last “experiment” it failed miserably and windows was totally trashed. Well not totally I could still boot but it was full of errors that only got worse as I attempted fixes. Ended up buying a new drive, restoring from my original restore CD and then installing only minimal programs. I kept the old drive to access data as I needed it. I must say things run fast now. Now that is a good registry cleaner ;-)

    Personally, the only cleaner I found reliable is myself and regedit. I’m more careful then any of these programs about what I delete (AOL crap)

  • Roy Turnbull says:

    In searching for info on registry cleaning software, I found only one true test: “Langa Letter: Testing 10 Windows ‘Registry Cleaning’ Software Packs” (From the October 10, 2005 issue of Information Week). Here is the link:

    Result: only 2 of the 10 tested programs worked. Two of the programs that had poor performance were highly recommended elsewhere. The two that performed well: JV16 PowerTools and EasyCleaner (The second one is free).

    The testing could have been more complete, but it was the only evaluation anywhere I could find that didn’t base ratings only on features or ease of use, but actually had a structured test to evaluate performance. I didn’t read all of the posts, but did notice favorable mentions of these products, and warnings against several others.

    Caveat Emptor

  • Darkan9el says:

    I use JV16 on a daily basis and it is more than just a reg cleaner its system management program. the reg cleaner gets rid of rubbish, that does not mean it speeds the system up, but just dusts behind the filing cabinet.

    I also use another registry program called Registry Workshop this is a great program for searching the registry but does more besides.

    As for actually having a registry I’ve read recently that a registry isn’t actually necessary and that programs just require an ini file to run. I have programs that do just that on my U3 stick and on my flash drive.

    So why exactly does micosoft want every PC to have a registry?

  • Lipsknot says:

    Mate I just ran Ccleaner on vista and i deleted 114.1 Meg and it runs heaps faster and is running fine.

  • poop ove says:

    Most of the registry cleaners allows you to select the entries you want to delete. So if you are going to use a reg cleaner id say, learn what not to delete before you do.

    Otherwise just dont use them.

  • John R says:

    Registry Cleansing = Colon Cleansing

    The best thing you can do to improve overall speed is to keep your drives defragmented. You can use DEFRAG that is included with the OS, or if you have a lot of activity on you PC, get a really good one like Diskeeper.

    Next best, especially if you turn your PC on and off every time you use it, is to educate yourself about processes that start up when you start the OS and delete or quarantine the ones you don’t need using msconfig (also included with the OS). No lessons here, but you can find out how to do this with a few Google searches. Unless you are really cramped for memory, most processes that start up at boot time just set there.

    Also run a good spy bot cleaner because these processes affect your browser significantly.

    Mess with the registry ONLY when you need to and only with clear instructions that you are comfortable with, a registry backup and a way to reinstate it if all goes to hell.

  • Brian E. says:

    The only reason I am posting is that I have come across a new Reg Cleaner called RegCure. I am not sure if I want to buy it because, I do not know if it will back up first, let me delete what I want or make a restore point. I ran it on my fresh install of Vista, 2 months old, and it came back with 913 items that need to be fixed….LOL.. Its got to be kindding.

    I am a PC tech. I do not trust Reg Cleaning programs. I think they can cause more problems then solve, especially if you do not know what is being deleted. I have tried JV16, thought it was OK. Tried RegCleaner, I thought it did a good job. Tried RegDr by PCtools, I thought it did a good job. What I like the best is Ccleaner. It allows you to delete what you want, period. I also use Diskeeper in auto defrag mode. This program keeps the drives inline and running fast.

    Just be careful on what you let delete for you. Find out first what files do what in the registry. And, no I do not use any of these programs regularly. Thats why I am researching now, because I am running Vista and this new program RegCure says I have issues…LOL. What ever..


    I use registry cleaners on a REGULAR basis , I am a poor lonesome grassroot user , no IT , no developper ; I Sticked for a long time to JV 16 PT regarding registry till I got “errors ” which were false positive (even with JV16PT YES!!!!) ; I asked on he forum precise questions about them and never received a satisafactory answer. NEVER; there a couple of IT Gurus just eluded my questions.But false positive , is apparently the common law with registry cleaners !!!! Apparently and I do not know why ; therefore I always test one by comparing the results with another one ; there is in my view no cleaner which makes magic tricks but there are very good tools to be used with extreme caution : that’s the point ; if used that way , these tools ARE useful.

  • rexus says:

    Yeah well, Vista has a very efficient system repair accessory… had to use it since Registry Winner screwed up *something* so badly that windows refused to boot.

    It detected cca 1300 errors (?!?) and among many “errors” was also a system restore utility… yeah, right. Maybe few programs are OK (like CCleaner, never did something like this to me), but in general, avoid this stuff, especially on Vista.

  • miklskon says:

    WOW! Have I gotten an earful (eyefull) reading all these posts ( yes, each and every one of them!) Many thanks to all of you who have contributed to this discussion! I am much the more wiser/knowledgeable for having listened/read each of them, both pro, con, and all points in between it would seem.

    Seems like the differences voiced in this discussion much represent the issues at hand, and that is you just gotta do your homework and use some common sense – good judgment skills when making these kinds of decisions.

    And if you wait to use or not use any so-called registry cleaners AFTER you have encountered a problem, or series of problems, then you probably ought to go back to square one and construct a good solid backup and restore policy on your system. For some it seems that this BU&RP would simply read wipe out everything and start over. OK, if that works for you, but of course that goes without saying, providing your personal user files are not hanging out there somewhere and in harm’s way.

    ( We have been saying “back up your data” to end users since the dawn of the IBM “Personal” Computer August 12th, 1981, and now here some 27+ years later, how many folks even do that? Let alone BUY their software and keep track of their licensed copies and keys?)

    Anyway, back to the bottom line…
    to use or not to use registry cleaners?

    For clarification, and I think most of us understand this, if a so-called registry cleaner frees up MBs or GBsof hard drive space, it was doing more than just cleaning up the registry. Obviously it was cleaning out temp and temp internet files and the such as well, so those points are not really relevant.

    I do think Ed’s original thesis still holds up well. In a nutshell, as I read it, “Show me the money!” OR rather, in this instance “Show me the performance stats!”

    OK, yah, it might seem that some problems that may have been slowing down the system were corrected by a registry cleaner, but what was the actual problem entry(s) and can you actually verify that that one action was what actually corrected the problem(s)? or were other corrections/actions also relevant?

    I think Ed stated it very well in the beginning, and that is that a registry scan might be valuable in pointing to a specific problem area, but then you could go directly to that specific entry and deal with it manually, instead of risking throwing the proverbial baby, or rather many babies, out with the bath water!

    OK, some have reported good results with a number of registry cleaners. Seems like JV16 and CCleaner have good reports, but remember CCleaner does MUCH more than just “clean” the registry. But some severe problems have been also mentioned by users as well.

    So we simply ask the question, “Is is really worth the risk? Is is a necessary risk?”

    I have only been working with PC’s since 1984 and I have yet to be able to affirm that any so-called registry cleaner has actually singularly improved the overall system performance of any of the 1000’s of systems I have worked on. To be sure there is an awful lot of hype out there, but little if any real tangible evidence to support their claims.


    My take on all this is simply to say that to date, general registry cleaners are probably not worth the risk of major problems ( let alone the loss of time and money! ) unless, of course, like some users, you could care less about the whole system and would just assume wipe out all and reinstall all.

    Start with a clean system.
    ( Don’t talk to me if you got your PC from a Pawn Shop!)
    BUY & Install only original and licensed software.
    ( Don’t talk to me if you use pirated OS or software! )
    Keep track of all the original discs for OS and Programs.
    Minimize just “trying out” software on your computer.
    Learn to backup your critical data on a regular basis.
    ( Know just what is critical and just how to back up! )
    Keep security programs current and up to date,
    ( current is related to license and version;
    up to date is related to definition files )
    & RUN THEM on a regular basis!
    Employ a good reliable disc imaging strategy, such as ghost, disk image, or others to create master images or hard drives of known good configurations.
    Don’t let others use your computer AT ALL!!!
    ( They don’t call them Personal Computers for Nothing! )


    That’s my two cents, and even though it takes another 98 cents to make a dollar, even the humble dollar is depreciating even as we converse here presently.

    Thanks to one and all once again. miklskon