There have been many posts indicating that uninstalling Rx and defraging a drive is not necessary. That once Rx is installed all that is necessary is to use the snapshot defrag utility that is part of Rx. This makes no sense to me at all. Snapshots are a record of where data is (or was) on the drive. These locations (the location of the data) are protected by Rx in the event that they will need to be recovered through a rollback. Further more these records are kept on a portion of the drive that is hidden from Windows. I can see how if you have deleted a snap (or multiples of snaps) that a defrag of the snaps would be beneficial from the point of view that it will make it easier for Rx to keep track of where the protected data and the relevant hooks are located but how does this defrag the physical drive? Frankly I do not think it does, or can. Through daily use the drive gets fragmented, Rx will record this fragmentation as snaps and the location of the fragmented data will be protected. If the drive is then defraged (not recommended with Rx installed but for the purposes of this discussion we will assume it has been done) RX will take another (probably large) snapshot and protect the locations of the moved data. If this snap is subsequently deleted defragging using Rxs defrag utility will reorganize the snapshot info and will (I believe) free the protected space, but it does not move any data around on the physical drive. If this is correct it follows that by simply running the snapshot defragger you are in no way defragging the drive and thus it would be beneficial to periodically uninstal RX and run a 3rd party defrag program. If I am wrong about any of this I would appreciate it if someone would explain explain to me why.