I've just tried to access an external drive which I have used daily for a while. I get the followingmessage: Volume does not contain a recognized file system. Make sure all required file syatem drivers are loaded and that this volume is not corrupted. Previous to this message I am told that drive must be formatted before being used. Can anybody explain what may have happened and is the drive recoverable? When trying to use a recovery system, the drive is not recognized.