Richard Kirk wrote: > Thanks for looking at this, particularly as I suspect this is an OS problem. > > I am running sudo /usr/local/bin/spotread -e -v -D9. I connect to the > instrument, do a > self-calibration, and then quit. > > I have attached a zip of the co bined stderr and stdout in spotread_log.zip, > which will > unpack to spotread.log ( 370394 bytes ). Hi, I don't really have much of an ideal as to what will cause poll() to fail after working successfully, apart from something like the device being closed on it. I guess there's a possibility of something like that being an explanation, some daemon or server clobbering the USB port which mightn't be able to happen when spotread has it open as root. Is there something like an old version of mtp-probe / libmtp running ? It was known for clobering color instruments. (look in the udev configuration). Graeme Gill.