Whenever I demo Vista to Partners and Customers, one of the areas I talk about is around Shadow Copies, or in other words, Previous Versions, and one of the common questions I get back is 'How much space does this consume on my machine??'  Well, let me clarify, but first, let me explain what Shadow Copies are all about...

Taken from the incredibly informative Vista Help and Support... "Previous versions are either backup copies—copies of files and folders that you back up by using the Back Up Files wizard, or shadow copies—copies of files and folders that Windows automatically saves as part of a restore point. (Shadow copies can be copies of files on your computer or shared files on a computer on a network.) You can use previous versions of files to restore files that you accidentally modified or deleted, or that were damaged. Depending on the type of file or folder, you can open, save to a different location, or restore a previous version."

For the purpose of this post, I'm going to focus on the Previous Versioning of documents, as it is something easy to demo, and incredibly useful.  We've all been there, we've opened a document, made a few radical changes, and instead of choosing to Save-As (because you want to keep the old version too) you've selected save, and then you have closed the document, so there is now no option to go back and undo those changes.  That's no good is it!

Well, my friends, Vista has the answer.  All you have to do is right-click that document, select "Restore Previous Versions" and this is what you will be presented with...

As you can see, not only can I restore from the shadow copy that I have recently made, but I can restore the backup that I made too!  You can restore to multiple shadow copies, so if I'd changed the document 3 days ago, 2 days ago and yesterday, I could go back to either of those!  One thing to remember is that if you go back to the earliest one, you won't be able to come back forward again.

What about if you have deleted a file, and need it again.  Can you restore from that?  Yes you can!  You can right-click the actual folder that contained the document before you deleted it, say, My Documents for example, and simply right-click that folder, select "Restore Previous Versions" and you will be able to see the folder contents from before you deleted the document you are interested in!

Can you turn this functionality off?  Sure, but why would you wnat to?  Can you apply it to multiple partitions?  Yes you can!  Simply go to control pane -> System -> System Protection...

I can simply select the partitions that i want to monitor for shadow copies.  Easy Peasy.

One thing you may be thinking is, if Vista takes Shadow Copies of all my documents etc, surely this is going to hammer this disc space i have remaining, right?  Well, if you pop over to The Filing Cabinet, you will see that the default set aside disc space is 15%.  You can modify this, and details are all found at that link.