Yes, sorry. Anyway I got home last night and the copy had hung, couldn't get windows to shut down or restart. BIOS wasn't seeing the 3 TB drive. I didn't have another cable to hand so I switched ports on the m/b, it came up in BIOS and now works fine.

No idea what's going on as I'd already copied my music files (35000ish) the same way with no issues. It's a brand new Acer PC, I've never had a port on a m/b fail before, but could that be it?

I'll see if I can find another SATA cable at work, but like I say it's working fine in the other port.