We have reproduced a problem with PortaGig 50 and USB under Mac OS 10.4.11. If data is transfered to or from a PortaGig 50 in this scenario, it may cause the computer to hang and/or crash. Windows, Leopard (Mac OS X 10.5), Snow Leopard (Mac OS 10.6) and above are unaffected. FireWire connection on under Mac OS 10.4.11 appears to be unaffected also. We are working to resolve this problem as quickly as possible. In the meantime a workaround is to use FireWire on Mac OS 10.4.11.