Thanks for this. There’s a lot of stuff installed on the machine but nothing jumps out at me as a likely cause. Are you connecting the NPC via a USB hub? If so, it might be worth bypassing that, see if it makes any difference. Other than that, I’m running out of ideas.
I was connecting directly with a Cardas 2.5 meter USB cable. I also tried a 2 meter Belkin Gold cable (same one that works with the mini with an active USB extension cable). I’m stumped too. Thanks for all your efforts Paul. At least I know I can use the Mini if it’s really important.
OK, thanks. Sorry I couldn’t help.
No worries. You did help eliminate some possible causes. At least we now know that if this issue comes up again it may be related to the particular computer. 
Hi Guys.
I have the same problem with firmware update. I tried two different Fat32 sticks (4 and 8 GB) and nothing happened. Who can help me?
Contact PSA support directly (Dave and Dennis helped me). If you have an early version like mine, there is a problem with the boot loader firmware. That firmware cannot be updated in the field (I’m told) but they were able to send me a USB stick that worked. They may also have another fix by now.