Off-the-shelf external USB drives normally are setup to work with computers that utilize CIFS type filesystems. rsnapshot uses a "hard links" feature that is unique to Linux/Unix filesystems (ext3). "Hard Links" are not supported on filesystems such as: '''"smbfs"''', '''"Samba (SMB)"''', '''"FAT"''', '''"FAT32"''', '''"NTFS"''', '''"CIFS"''', '''"vfat"'''. Please note that "Amahi Greyhole" mounts Amahi shares that will look like "local disk drives" '''''but''''' these are Samba (SMB) mounted shares. The An external disk drive will have to be prepared for a Linux/Unix filesystem, in particular ext3. Why? ext3 has been around for sometime, is stable, and "Windows" computers have Open Source drivers available that can be installed to gain access to an ext3 drive.