(2015-01-25, 23:40)joah_fr_Alberta Wrote: Thanks for the reply, I believe I am running XBMC. Perhaps then I should be looking at the Pi's ntfs driver? I wonder if it might be the blue 3.0 connector on the external drive ...
You are running XBMC (== the application) on top of an operating system (RaspBMC, OpenElec, RaspBian or something else).
I requested you to mention which operating system you use, not the application...
A driver is not a connector! A disk driver is a piece if software running in the operating system and enables the operating system to attach a connected disk to itself so it can be used by the person using the system for storing files.
If the ntfs disk driver is not installed in your operating system then it will not be able to read the disk.
If the disk driver is not the latest version then it will not be able to use the latest features (whatever these my be) possibly limiting your disk access.
Since you say you can use a 2TB disk drive but not a 4 TB one then there may be differences between the ntfs formatting of these drives that makes them sufficiently different for the Pi ntfs driver not being able to cope with the 4 TB drive. One example may be the sector or cluster size used on them.
You should use a disk utility on a PC to examine the two drives to see what is the difference.
Do you already have files on the drives?
If not then a reformat might solve the problem.