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Does a repair install redo the registry?

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I was just wondering what a repair install does to the registry. As far as I can tell, it does nothing so if you have some corruption in it a repair install won't fix it.

Any input appreciated but please don't state something as fact unless you know for sure and can demonstrate it. Thanks

Edited by -X-
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I was just wondering what a repair install does to the registry. As far as I can tell, it does nothing so if you have some corruption in it a repair install won't fix it.

Any input appreciated but please don't state something as fact unless you know for sure and can demonstrate it. Thanks

I don't know the answer for WinXP.

FWIW, the last time I did a repair install it was on Windows 7 ( see here ), it has been years since I did this on a Windows XP computer and I know it wasn't as controlled as that Windows 7 occasion. I mean, I don't have any snapshots of an XP repair before and after to examine what was really done by the process. In that Win7 case I did grab filelists and registries but even they are not perfect because I was rushed. Anyway, let me start by explaining one thing - the only way to say with certainty what was actually done is to get copies of the registry, registry exports, and filelists, but done from outside the operating system. Either pop out the HDD and drop it in another computer setup for this kind of thing and collect the registries and a thorough filelist, or alternatively, if you have access to ERD/DaRT you can boot it up and do the same plus a complete registry export from its registry editor, dumping to a flashdrive. The reason I am explaining this is because filelists and registry exports done on a live system are limited, not everything shows up. Comparisons using them will be totally inconclusive.

Now I can say that the Win7 repair process is a really impressive thing they pull off with multiple reboots and replaced in-use files and such. It preserves installed programs and "settings", this means that non-Windows files are not tampered with, and most importantly the registry with its myriad intertwined keys and data are carried forward - but - additionally, Windows is reinstalled as well. ( Again, I cannot answer about WinXP here ). When I did some diffing ( NOTE: this was a bear of a task, huge registries, needed bigtime CPU overclocking and other prep, Windiff froze, ExamDiff finally worked ) I learned that large swathes of the original registry were copied verbatim, perhaps the whole thing at once, and then machine settings were punched in and/or completely replaced which "fixed" so-called registry corruption. However, "corruption" means different things depending on whose asking. Real registry corruption, like a broken database from file defects like missing delimitters causing a key to run into another should be fixed because when the original file is read-in and written-out they presumably use error checking to toss any bogus keys or data. Corruption can also simply mean changed values in machine keys like device driver settings that leaves hardware not working properly. These would also be fixed in the Win7 process by the ( presumably ) 2nd step that reinstalls Windows. So I would say IMHO, that in Win7 at least that the "registry corruption" is in fact corrected as well as it can be. User programs that were buggy before will still be buggy though, that is by design because no user items are tampered with.

My suggestion is this. You have an WinXP installation with a possibly corrupt registry? Get another equivalent HDD and clone this WinXP system drive from outside the operating system using HDD tools like Seagate DiskWizard. Now you have a nearly identical copy to work with, use this new HDD for experiments. Do what I said above, either pop the clone into another reliable computer and grab the filelists and registry hives or boot ERD/DaRT and get them that way. The latter has an Explorer app for poking around the HDD and collecting files, a CMD window for doing a filelist and a registry editor that can export. Dump them all to a flashdrive marked "before". Then after doing a repair install, repeat the process and get files "after". Later on, 'Diff them to see exactly what changed ( if anything ), you will then have an absolute answer to the original question.

P.S. you will notice from that link that I was also trying to determine whether I could do the repair install directly from the HDD. That means copying the full updated SP1 ISO to the HDD and executing it from there without using an optical. The answer was yes, it works. But again, that is Win7. Now it should be do-able for WinXP considering that there are ways to install from a flashdrive ( and I believe from a HDD ), but I can't recall ever trying it. I suggest that experiment might be done separately to not make it too complicated. But the good news is that if you work from a cloned copy, you can always just start over with another clone if necessary. I would never do this on the one and only system disk though.

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Windows XP CD has the option for a repair install. I did it once and it is the same with the Windows 7 thing as Charlotte describes it. It restores the default Windows files and registry entries (which means that you loose any service packs or updates installed) without affecting other files and registry entries as those of the several installed programs.

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+1

Any BAD stuff still in the registry and BAD stuff on the OS remains. JUST the WinXP Files and Registry from the Install Files.

Done this multiple times. Just did it on a friend's computer LOOOO-ded with trojans/viruses (pr0n-dog). Still cleaning up the non-OS stuff as "we speak"..

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To my knowledge a repair install replace/remove the system registry hive but doesn't remove/repair other registry hives.

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I think it just executes the .inf's, thus overwriting what is existing in the registry, but I have no hard evidence, so I didn't post before. :)

GL

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In my opinion, its better and faster to repair/replace manually (e.g. with a Parted Magic - CD/USB)

c:\windows\repair\ and from the *.sav Files in c:\windows\system32\config\ (<- this is the used Registry)

Edited by e-t-c
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I'm gonna have to run some experiments in a VM to get a definitive answer.

Thanks for all the input!

I'll post back whenever I get around to it.

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Well I conducted one experiment but it's inconclusive because it only involves current user. I deleted HKEY_CURRENT_USER\Control Panel and it didnt delete fully. It told me it was in use but it deleted most of the content. Some content auto regenerated itself before I did the repair install. After the repair install, nothing had changed.

Now on to local machine...

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Well I did local machine and same thing. I deleted Wireless Zero Configuration (WZCSVC) service and it did not add it back.

So I guess a repair install does jack shit to the registry even though I see it loading the hives during text mode.

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The original backup copies of your registry files (located in the %systemroot%\Repair folder) are replaced when the reinstallation is completed. These original registry files in the Repair folder were created either when you started Windows XP or when you last used the Backup utility to back up the system state. If you think that you might have to use the registry backups after the reinstallation is complete, copy these registry backup files to another location before you perform the reinstallation.

Source: How to perform an in-place upgrade (reinstallation) of Windows XP
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Well I did local machine and same thing. I deleted Wireless Zero Configuration (WZCSVC) service and it did not add it back.

So I guess a repair install does jack s*** to the registry even though I see it loading the hives during text mode.

And what happens if you delete almost everything? Some things will have to be restored, won't they?

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I mean that if you do a repair install it must restore the basic keys of the registry in order to repair it.

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Wireless Zero Configuration is a "basic" key or is it not. Give me an example of a "basic" key..

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