ok so now my max transfer rate is set at 0x00FFFFF, I've read that that is should be 0x1fe00 BUT if I change this figure now will I lose/ affect existing data??
You can change it without data loss.
But correcting the MaxTransfer value does not magically repair all corruptions. If a file bigger than 128 KB has been written with the wrong MaxTransfer value, it is most likely corrupted on disk.
