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An error after running a registry cleaner is, unfortunately, all too common. I'll point you at an article with some steps to try.

The "Windows Installer service could not be accessed" error message shows up. This problem started once I downloaded a registry cleaner. Now I'm not an able to use an Adobe file or download it.

In this excerpt from Answercast #88 I look at a problem on a computer after running a registry cleaner.

Error after running registry cleaner

Well, I do have an article "How do I fix the Windows Installer service could not be accessed?" and I'll certainly start by pointing you there.

But, what I want to do is point out that this happened after you ran a registry cleaner.

This is exactly why I don't recommend you run registry cleaners. They are simply too dangerous. They can simply cause too many problems of unknown origins.

Fully system backup

Now, what I hope you did was to have taken a full system backup prior to running the registry cleaner. If you had, you would simply be able to restore your machine to the state that it was in prior to running the registry cleaner and get on with your life.

If you are running the registry cleaner to resolve a specific problem, then let's diagnose that problem instead of running a registry cleaner.

Periodic registry cleaning?

Finally, if you're running a registry cleaner just because you think it's good to clean your registry periodically? Well, this is why it's not.

I actually have an article, "What's the best registry cleaner?" and in my opinion the best registry cleaner is no registry cleaner at all. Again, specifically because this kind of thing happens.

(Transcript lightly edited for readability.)

Article C6249 - January 16, 2013 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

Bill Landau
January 16, 2013 7:29 PM

I'm not as convinced as you are that registry cleaners aren't useful. But the only one I would use on a client's computer (or mine) is CCleaner. And CCleaner *always* asks if you want to backup the registry before cleaning, which can allow you to fix a problem like this.

That said, I have used CCleaner probably hundreds of times without problems.

January 16, 2013 7:57 PM

Before going through the exercise of restoring his PC using a full system backup image, the poster may want to first try using System Restore to revert his PC to a point in time before he used the registry cleaner. System Restore may provide a quick and easy solution here.

January 18, 2013 9:33 AM

Well there wasn't a problem with the registry in the first place so why risk it anyway. Using buzzwords such as 'Fix', 'Repair', 'Critical Errors' and so on, they mean nothing - still a program which is designed to remove an entry. Regular usage of registry cleaning can fragmented the registry. Orphaned registry entries are harmless and doesn't impact on the performance.

Registry cleaners do not feature at all on my must have list of programs and this article is a perfect example of why people should not be using them, backups or no backups available in the program, I still steer far away from them.

bob price
January 18, 2013 11:45 AM

Exported my reg and it's 380mb. So, deleting even thousands of strings from the reg with a cleaner is equivalent to snipping off a small corner of page 257 of the Sunday edition of the LA Times.

Over the years, I've run full diagnostic performance tests before and after running cleaners. Zero improvement. Complete waste and high risk.

January 18, 2013 11:19 PM

My first year of computing, registry cleaners were being recommended by the respected magazines. But using a highly rated one resulted in my having to reinstall Windows. After which a very smart tech support rep told me the same thing Leo and Bob Price say in this article, don't use registry cleaners. Also that each registry entry takes such a miniscule amount of space on the computer that it is not even worth the trouble to remove. Since then will occasionally run C Cleaner's reg cleaner, scan only. If there is an entry I know is safe to remove, ie, regarding a program no longer on the computer, will export the key (back it up) and delete only that key. The rest are left alone. The results - no loss of computer speed over several years, and no further problem necessitating a reinstall of the OS.

Old Man
March 26, 2013 10:15 PM

I had the same experience as Bonita. After running the registry cleaner, nothing worked properly. I tried the restore, but it didn't work - I've never had one work for me. I ended up having to completely rebuild the HD.

I've run a few of the free scans and then looked for whatever the scan said needed to be changed. I couldn't find those entries anywhere in the registry. So I really don't trust them much.

Although this is too late for the original poster, I follow the idea that if it's not causing problems, leave it alone. I'm not getting any registry error messages, so there's no reason for me to "clean" the registry. And, as Bob said, it isn't taking up enough room to be concerned about it.

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