I am having a hard time setting up Time Machine to back up to an external hard drive that I have configured to run both on PC and Mac. Initially, my files on the external hard drive were "read only" files when I tried to access them from my mac. So I have downloaded an app called MacFUSE to run within my Mac to write files on the drive since it is formatted in NTFS. I was able to save files on the disk, however, for some reason I am not able to use the external hard drive to show up on Time Machine. What am I doing wrong? Thanks for the help!