There are two major partitions while initialize HDD installed in ME1.
Linux partition is for timeshift and AV in record space.
FAT32 partition is for photo/music/movies storage space.
If you would like to copy recorded video to PC, then you need copy video to FAT32 partition first, and then copy to PC through USB connection.
Copy to FAT32 method :
Playback -> Title Edit -> Copy to FAT32 partition
Video will copied to \REC folder.