System Restore won't work (Windows XP Home)

[Superben]

I am getting a bizarre error message when I go to System Restore, it pops up saying, "The procedure entry point RemoteAssistancePreparesSystemRestore could not be located in the dynamic link library WINSTA.dll" I have absolutely no idea what this means, and I don't know how to fix it. I can't create, or restore - restore points; something I need very much.

[WyllyWylly]

The error means that you have a system DLL that is the wrong version. Try running the System File Checker (Start - Run - SFC /SCANNOW) to see if it restores the proper DLL file.

[Superben]

I actually fixed this problem, I downloaded new Windows XP updates, and everything works now.

[Fafner]

Could you tell me more about System File Checker. Out of curiosity, i ran "scf /scannow" to see what would happen. The text box reads "Please wait while Windows verifies that all protected Windows files are intact and in their original versions." I didn't put the Windows CD in the drive, so each time it tried to copy a file, I skipped it. I just wanted to see what it would find. During the entire process, it tried to copy a file 183 times, which means that either it tried to copy the same file 183 times, or else I have 183 bad DLL's, which seems unlikely. It's the part about "in their original versions" that concerns me. If I ran sfc /scannow as intended, would it revert to the original DLL's and therefore undo all updates that have been applied, not to mention SP-1? If this is the case, then it seems that System File Checker is of limited utility. Can someone explain?

Fafner

[WyllyWylly]

The System File Checker is part of the "new" Windows File Protection that was introduced with Windows 2000. Although Windows 98 includes a similar utility, it's quite different in operation. Essentially Windows File Protection works like this: Windows (2000/XP) maintains a cache of known good system files. DLLs and their kin are more often than not interdependent and the version of each is important. When a program, such as a service pack installation or application install, replaces one of these cached files, it's overwritten - or should be - with the known good version in the cache. This enhances system stability. In order for the cached version to be updated properly during a software installation, it must be done properly (preferably using the Windows Installer).

The System File Checker compares the cached versions with the ones that are in use, and replaces them as necessary. Programs that do not use the Windows Installer are prone to overwriting system files, a phenomenon affectionately known as "DLL Hell" from past experience. Microsoft has a few articles that further explain this feature.
<UL><LI>Description of Windows XP and Windows Server 2003 System File Checker (Sfc.exe)
<LI>Description of the Windows File Protection Feature
<LI>Registry Settings for Windows File Protection
<LI>MSDN Documentation on Windows File Protection
<LI>Windows File Protection on Windows 2000 and Windows XP[/list]In your case, using the utility would replace service packed versions with the correct ones, since service packs update the cache and maintain the integrity of the system. SFC may be limited in some regards but it's always an excellent starting point when things are going wonky.

Hope that helps!

[Fafner]

Well, it sort of helps, and I thank you very much for the detailed reply. But I still have a pretty basic question: What should I do? I read the articles referenced in your post; parts of them were over my head, but I understood some. Your statement "using the utility would replace service packed versions with the correct ones" has me a little confused. Are you saying that the files installed with service packs are not the correct ones and need to be replaced with the originals? When I ran sfc /scannow, I was repeatedly (183 times) prompted to put the Windows XP Pro CD in the drive so that it could copy the correct file. But haven't some of the files on the original CD been superceded by files from later service packs and Windows Updates? So wouldn't the SFC undo these updates by replacing later versions of the files with the originals on the CD? What am I missing here?

Fafner

[WyllyWylly]

<hr>What should I do?<hr>

Allow Windows to use the CD as necessary during the file check process.

<hr>Are you saying that the files installed with service packs are not the correct ones and need to be replaced with the originals?<hr>

No, definitely not. Service packs contain updates to the system, and are the latest version - and should not be replaced.

<hr>haven't some of the files on the original CD been superceded by files from later service packs and Windows Updates?<hr>

Yes - some have, and some haven't. There are a lot of different pieces that make up the whole, and updates and service packs address very specific components of the overall system. Not every file that makes up Windows is replaced with a service pack/hotfix, just the affected ones - just like your car gets repairs to fix failing components, or is taken in for recall service to prevent them.

<hr>wouldn't the SFC undo these updates by replacing later versions of the files with the originals on the CD?<hr>

No, because a service pack/hotfix properly registers the updated file version that it replaces with Windows. This is part of the previous answer to your other question...Service Pack and Hotfix files cache the correct version and pull them from there. All of these parts work together: service packs/hotfixes, the WIndows Installer, and Windows File Protection, and a few other things.

Hope that clears it up a little more....but if not, post back. <img src=/S/smile.gif border=0 alt=smile width=15 height=15>

[Fafner]

Yes, thank you very much. This answers my questions. Here is one more question before I sign off, but I can probably guess the answer: Is it likely that I have 183 incorrect system file versions on my system, a system that really isn't giving my any problems (with the exception of an svchost error message "unable to write to memory" whenever I shut down -- something I want to research a little more before posting about it)? Could my system have become that much out of whack without my seeing more problems?

Thanks for your help. This forum is great!

Fafner

[WyllyWylly]

Ideally, DLL files and their ilk are supposed to be backwards compatible. That means any newer version will work just like the old one, but in practice that's not true. I have to claim ignorance on why you would be prompted so many times, but if your system is running OK, that's a good thing. I'd still let the system file checker go, just to ensure a clean bill of health - but perhaps you would want to run the backup tool in XP and back up the system state first, just to feel safer.

The error you're getting could definitely be related to system files, and you could also reapply Service Pack 1 to make sure everything is up to date - and then run SFC afterwards. Ah, the joy of computing!

[Fafner]

Thanks. I will follow your suggestions.

Fafner