This hint mentions it is possible with Disk Utiliy, but only after initial unmounting. It is possible to transform a disk with NTFS into a Mac disk with HFS+ format.Writing to NTFS disks still isn't possible all NTFS disks are mounted 'read only.'.See the bottom of this hint if you are interested in what kind of issues I had using 10.3.8 which were resolved in 10.4.1. Reading from NTFS disks seems to be very stable now in 10.4.1+.As I said, several things here may not be big news to some readers, but I am sure at least some people will appreciate an overview, so here we go. Since I have been interested in using disks usable by both Windows and Mac computers and found info in several other hints on this site which, however, are sometimes rather old and have a long comments section which take a while to read and new points spread in between, I thought maybe some people are interested in a short overview on what can currently be done in this area. This has saved me a lot of trouble: It is now possible to reliably read NTFS disks (NT File System, as used by modern Windows versions such as 2000 or XP) under Mac OS X 10.4 (tested under 10.4.1).