Shadow Copies are copies of files that users can view and use to restore older versions of files and folders. (Even those that have been deleted.) Shadow Copies are available for files stored in network folders. (They are NOT available for files on your C: drive.)
Shadow Copies are created on the servers twice every weekday at 7am and noon. The system checks to see which files have changed since the last Shadow Copy. It saves these changes, and keeps track of when the copy was made.
As more Shadow Copies are made, and the storage allocated for this purpose fills up, the system automatically purges older copies. This information provides the ability to recreate the file as it existed at any of those moments in time.
Important Note: Shadow Copies are NOT available for folders or files on the hard drive of your computer.