My own take is that a registry defragmenter is useful, but really, cleaning the registry?
Any stat on how much room in kb is being saved? And, without a reg defrag, the space is still allocated, just has no entry. I wouldn't expect that would speed anything up as the tree is still X size.

I share Carol's opinion and experience, I've had very lousy results with registry cleaners/doctors/fixers. And many of them show up much later.

Norton win doctor is my main cleaner and is safe to use as it appears not to be a deep scanner like the one in the link below or the topic starter ,i have yet to have a prob with it in stuffing my comp up(i found out the hardway) and it's 2 years now,how many mb does it save on the disk i can't say as neither apps give an amount,what i do see is a large list of obsolete keys,folders,shortcuts etc from installs and uninstalls,tho when it comes to a system sweep cc shows the mb you can save

http://www.ccleaner.com/


EDIT: If and when one does a backup and lets say you decide to do a full system backup it pays to have a spare HDD to test it on the last thing you want is for there to be a corruption on one of the backup disks and cannot continue (it maybe possable to make a clone of the faulty disk and with luck it may work) or you'll end up doing yet another windows install...lol... best backup is cloning from one HDD to another

My bad i forget that some may not tinker with dual HDD's on the one comp and yes it would be necessary to have another comp,that aside and a little off topic but a forum member may need help one day take a gander at the site below

http://www.radified.com/

EDIT: The green page from that link will auto direct you ,just wait a mo then look for the link at right for the forums,any cloning queries you have they can help

I have been using Registry First Aid for some time now and find that it's excellent....

I've been using Registry First Aid since version 3.1.  It's now on version 5.0.1.  It has been excellent for me.  I never had a crash and never had to roll any RegEdit backups.  Well ... there was a System Restore once, but that was many years ago.

Registry First Aid won't fix any entries unless you approve them, so you stay in complete control.  It also will rank the safety of each proposed fix Green, Yellow, or Red.

My only gripe is when I first ran it, there must have been over 1000 registry errors.  It took me 2.5 afternoons to look at each one of those.  Most can be fixed or deleted easily, but some require 3-5 minutes of research even when you know what you're doing.

It does provide quick registry-key links to RegEdit for doing the research as well as the file directory tree, but you still need to figure out what some installer (or uninstaller) couldn't figure out for itself.  This takes study, even on a system that you are familiar with.  I guess, if all the fixes were straight forward, you wouldn't need the registry in the first place. 

The Platinum version will also compress the registry.

It also has a feature to search out obsolete software entries.  For example, after uninstalling AOL, there are still 100s of AOL entries lurking in the registry.  You can have it search out the string "AOL" to find those entries, then determine if they're safe to delete.

AOL is so inter-woven into the registry that tracking down all its references for deletion purposes is hard.  I just don't have time to do it.  But if someone has written a smart uninstaller that can track down latent AOL reg entries automatically, please let me know about it.  I got latent entries for AOL client 7.0 & 9.0.

Cleaning and compressing the registry does make the computer operate somewhat faster.  I've been meaning to get Microsoft's book on the registry, but haven't had time as yet.

I dither between Registry Medic and Registry First Aid Platinum,... I'm with Registry Medic 4 (though I have a license for RFA Plat 5) because I much prefer the way it organizes entries found by class (active-x plugins and com, start menu, recently used file lists, uninstallers, help files, etc.)...

Well, Registry First Aid breaks them down too.  And you can sort either by their category or rank of fixing safety (green, yellow red).  But Registry Medic might break it down with better granularity.  I haven't tried that one.  Maybe I should.

... I find [Registry Medic] much easier to navigate. For example, it's nice to be able to clear the start menu items and other no brainer stuff all in one go without trying to wade through hundreds ... of entries.

Well, you can sort by fit-it-safely level, then fix all the green flagged issues together.  But a few of Registry First Aid's suggestions are not correct (even at the green level), so you should exam each one of them.  Usually at the green flagged level, you can just delete those bad enties flagged as green.

I've never seen any advantages from running registry cleaners....
defragmenting the registry, however, can bring some decent speed boost....

Tons of obsolete registry entries effectively fragment your registry.  Even removing some obsolete entires without defragmenting will speed up your system.  Applications will sometime wait for nonexistant service links to respond before timing out.  Your results will depend on how well your registry cleaner finds broken links and how well you know how the fix them.  A few registry problems require some research with RegEdit and your directory tree to figure out what some installer couldn't. 

The ... thing about system breakage is that it happens silently, obscure, and you don't find out until weeks later,...

All too true.  Don't mess with entries you don't understand.  The problem is some entries look unnecessary, but how can you really know?

I sent a suggestion to one of the registry cleaner developers suggesting a Windows registry knowledgebase be started on the web for each application key in the registry.  This way, by checking the knowledgebase, the registry cleaner can really tell if an empty entry is really needed or not by its application.

Quote

Even removing some obsolete entries without defragmenting will speed up your system.

I've never seen an effect of doing that, and it doesn't surprise me. Windows uses a binary search when looking up keys, which means that even to look up a key in 4.2 billion keys it needs to look at maximally 32 keys.

Deleting obsolete B-tree (registry) entries isn't going to speed up B-tree lookups much.  It might speed up logins/startup some.  The reason applications speed up when bad registry entries are fixed is because they aren't waiting for non-existent service/procedure (COM) calls to answer that were pointed to by some obsolete registry link that says this service exists when in fact it has been uninstalled.

This brings up an interesting programming question.  If your application blocks on a service call that's not responding, how long should you wait before giving up?  Should you inform the user at all (after all, most users wouldn't know how to patch the registry correctly in the first place)?  I guess this issue belongs in the programming forum instead.  Sorry.

Im new hear to and it works good, Man it  was that fast,Dam and i was looking for some other reg ,