Resetting Windows XP registry permissions

The other day I was trying to install Windows XP SP2 on a computer that had SP1 installed. I’m not sure how it got to SP1 (upgrade from XP, upgrade from Win98, etc), but I kept getting to a certain point that was telling me “Access Denied”. As I researched this it turns out it was a permissions error in the registry. The suggested answer was to reset permissions on 4 registry keys, but as I looked around the registry, there were all sorts of permissions that were wrong. I’m not sure what happened, but I did figure out how to reset the permissions back the default.

“Access Denied” error when trying to install SP2
This article explained how to use the SubInACL utility from Microsoft to set the permissions on certain registry hives. I guess this doesn’t specifically set them back to the default, but it allows you to set hives or keys to what you want the permissions to be.

How to reset security settings back to the defaults
This Microsoft Knowledgebase article does explain how to reset the permission to the default. It uses a utility that is included with Windows XP so it is very easy to use.

Remember, this tip isn’t just in case SP2 won’t install. If you have been messing around with the registry and changed permissions, this is a way to get them back to the default. And of course remember… when you are working with the registry, be sure you have a backup in case you do something wrong.

Comments 3

  • Sorry Bob. Somehow I ended up with the wrong link. It must have been something else I was looking at. I’ve fixed the links now and they take you to the correct sites.

  • Thanks for the post. Had trouble on an in place Winxp home -> xp pro upgrade. The main user had all these registry troubles even after I ran subinacl with:
    C:\Program Files\Windows Resource Kits\Tools>subinacl.exe /noverbose /errorlog=error.txt /subkeyreg HKEY_LOCAL_MACHINE /setowner=Administrators

    I ended up following the “reset default security permissions” article. and then copying what a good HKCU looks like from a working machine. the troubled machines HKCU had zero permissions set for some reason.

    wish I knew these articles last year when I ended up having to recreate a windows user to fix the trouble. (but that messes up outlook and such so it is far from ideal)

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