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Restoring the registry is similar to the way System Restore works. The results as a backup strategy may be unreliable.

I enjoy experimenting with computers: installing and running different software. Occasionally, I crash Windows and there's no way back except to reinstall the entire operating system. Right now, I know of only one way to remedy a completely crashed Windows; by having a separate hard disk where the entire computer image is saved. After an unrecoverable crash, I exchange the hard disks and make another copy. For an image, I use Acronis TrueImage. I use two operating systems on two separate computers: Win 7 and Vista.

Here's my question: let's say that I have 20 programs installed on Windows, Win 7 or Vista, and everything runs well. Now, after I install program 21, and play with it for a while, the computer really slows down. While trying to make things better, the computer is getting slower and slower. My question is whether just making a complete copy of the registry, by exporting it while there are only 20 programs installed, and substituting or importing after the registry went through the installation and changes with program 21 would in effect return the Windows OS to its pre-installation of program 21 instead of using the old image?

In this excerpt from Answercast #34, I look at the idea of keeping a copy of a computer's registry as a backup and restore option. It probably won't work all that great.

Restoring a backup registry

There's two answers to that.

  1. The quick answer is no. And there's a couple of reasons for that.

  2. The other answer is: that's kind-of sort-of what System Restore does.

It's one of the reasons that I don't like System Restore; it really doesn't work as well as we would like or as reliably as we would like it to.

System Restore

System Restore is trying to do exactly what you describe. Sometimes, it works: so that might be something to consider doing, but still be prepared for it to fail.

Now, the problem with just exporting the registry and restoring the registry is that when you install a program (program 21, in your case), quite often that program will make more changes than just what's in the registry.

  • For example, it may replace a common system file:

  • If that common system file is the source of the slow downs that you're seeing, simply restoring the registry isn't going to undo that from having been done.

  • The registry is a database of information; it's not going to actually affect the files that are installed on the machine.

That's not common, but it does happen.

Uninstalling software is different

The fact is that uninstalling software does something valuable. In many cases, it will revert software that's been overwritten by the install to its previous version if that software is shared with other programs on your system.

So the short answer is no, I would not do this.

Restore instead of swap

I'm not sure why you're swapping hard disks. The approach that I would take to do this (if you're doing this on such a regular basis) is actually very simple:

  • I would certainly use an external hard disk or a second hard disk to store my backup image.

  • I would use something like Acronis or Macrium or any of a number of disk imaging utilities.

Given that image then, if you decide you need to revert, I wouldn't swap around anything:

  • I would simply boot from the rescue media that's associated with your backup software;

  • And restore the image to your hard drive with no swapping of drives involved at all.

That to me seems less disruptive. It might, I suppose, take a little bit more time because it's going to be streaming an image of your hard disk back to your hard disk. In your case, you're simply swapping hard drives and maybe you've gotten really good at that by now.

Short answers

  1. The short answer to me is nope, don't use the registry. It's just not going to be reliable for the kinds of things you want to recover from.

  2. Consider using the backup programs in the manner that they were actually designed to be used, rather than swapping hard disks just restore the backed up image.

Article C5572 - July 11, 2012 « »

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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?

bob price
July 13, 2012 9:32 AM

There is one time when I export a full copy of the registry, and that is when I plan to open the Registry and make several deletes of folders and value strings. In case i mess up, I can import or simply double click the reg file and reboot to the former registry.

This does not happen often, but it happens. For example, I recently downgraded and installed FastPass thinking I wanted to try this password program. Something went wrong and I could not get it "registered". I used Add/Remove Programs to delete it. That was supposedly successful. After rebooting, I entered Regedit and did a search for "Fastpass". I found over 50 folders and probably +300 value strings that still existed for Fastpass.

I exported a full copy of the reg and then deleted all those Fastpass lines. It worked fine, so after a week with no problems, I deleted that exported file.

Add\Remove Programs does an extremely poor job of deleting all the values, which is why reg cleaners find 1,000's of errors in the reg.

July 13, 2012 9:57 AM

LEO: When I try to get an excerpt from answercast #34
and click on "backup and restore" I get an advertisement
from Verizon. I can not figure out how to get out of
that ad for the purpose of going on to read "backup and
restore" thus I can not read "backup and restore". Please email "backup and restore" from answercast #34.

Keep up the good work.

thanx. terry huff.

I'm not actually certain what it is you're referring to with "backup and restore". If it has a double underline it's not a link of mine, but rather a link specifically for the ad you're seeing.

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