Windows – Does exporting a registry key in hive binary format preserve permissions and how can I import them to another machine

windows-registry

When I export a key in the registry on my Windows 7 machine, I get the option of .reg or a hive file in binary.

What's the difference?

Does the binary hive file preserve the permissions? Example, I have a key, bfe, and it has various permissions for "nt service\bfe." Will the binary save save that?

How can I import that back in on another computer that has that key but broken?

Thanks.

Best Answer

The textual .reg format does not support WinNT security features; it only preserves the data exported, as you can see by opening the .reg file with a text editor.

The "hive" format is identical to the one used by Windows to store the registry itself. This means that it supports all features used by registry, including security permissions and ownership. You can examine exported "hive" files by using "Load hive" in regedit or reg load in command line, and import into the main registry with reg restore.

However, remember that users on Windows are identified by their SIDs; local accounts will have different SIDs on different machines, so you may still have to adjust the imported permissions manually. (Builtin accounts such as "NT AUTHORITY\SYSTEM" have the same SID everywhere. Domain accounts always have the same SID on every domain member.)

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Windows 7 – Creating a .reg File

I don't know how those quotes ended up in that file, but I would assume those don't work (maybe you copied it off a Wordpress blog).

Besides anything else, I think it should be like this:

[HKEY_CLASSES_ROOT\Folder\shell\PngCrush]
@="PNG Crush"

[HKEY_CLASSES-ROOT\Folder\shell\PngCrush\command]
@="E:\Programs\PNGCrush\crush.bat %1"

Windows – Is it possible to import a Windows registry file without destroying a system

Let me just get one thing out straight away, importing a huge registry file like you did is a bad idea.

When you export keys to a .reg file, you're simply creating a file that will contain instructions on how to re-create the keys you selected. Note that it will only take care of creating keys. Thus, when you later import the file, a merge will happen. Keys that don't exist in the registry any more will be re-created (which might be a horrible thing to happen) and keys that have changed will have their value overwritten (which might be just as horrible). Keys that were created from later boots of Windows will still exist after importing the .reg file.

A .reg file can even contain instructions to remove keys from the registry completely (although that won't be the case when exporting from the Registry Editor). So it is advisable to know exactly what a .reg file contains and what it will do. With a 480 MB file, it's very unlikely that you'll be able to know what will happen when you parse it.

At this point, I have serious doubts if you will be able to recover from this and get everything back to a proper working state. Luckily, the result of this doesn't seem too catastrophic. Good luck! If you have shadow copies enabled, the guide How to Restore Previous Versions of the Registry in Windows 7 might help.

I know that there are several guides online (like the one on the Windows website) that treat the .reg file export as a backup of the registry and, to some extent, it is. It represents a certain state of the registry at some point, but merging that state with a later state isn't really advisable (as you've just found out).

However, if I wanted to make a proper backup of the registry, I would copy the registry files from C:\Windows\System32\Config. Those could simply be replaced later to fully replace the state of the registry.

Best Answer

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Windows 7 – Creating a .reg File

Windows – Is it possible to import a Windows registry file without destroying a system

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