In the root of every drive is a folder called "System Volume Information". If your drive is NTFS, the permissions on the folder are set so not even administrators can get in there. What's the big secret?
The folder contains information that casual interference could cause problems with proper system functioning. Here are some of the things kept in that folder. (This list is not comprehensive.) •System Restore points. You can disable System Restore from the "System" control panel. • Distributed Link Tracking Service databases for repairing your shortcuts and linked documents. • Content Indexing Service databases for fast file searches. This is also the source of the cidaemon.exe process: That is the content indexer itself, busy scanning your files and building its database so you can search for them quickly. (If you created a lot of data in a short time, the content indexer service gets all excited trying to index it.) •Information used by the Volume Snapshot Service (also known as "Volume Shadow Copy") so you can back up files on a live system. •Longhorn systems keep WinFS databases here.