Now I have OS X 10.6.6 but problem occurred on 10.6.5 too. About "other profiling software": It is i1match in basic version, whom starts Profile Reminder on startup. The second is Monitor Reminder from Monaco Profiler. Both was instaled before (since OS X 10.6.4.) and did not affect to dispcal. I'm not able to uninstall this software, but I can't determine which files belongs to them. From some time (but I can't tell when) I saw new item on preference pane. It's X-Rite Device Services, which show state (on/off, calibrated, connected) for i1 iO and i1 iSis, (and both is on and disconnected). When I connecting i1 Pro, only "i1 iO" changes to "i1 Pro" as connected. Removing this preference pane from library doesn't helped. Felix [felix] wrote: icoms: About to open USB port 'usb:/bus93/dev2/ (GretagMacbeth i1 Pro)' dispcal: Error - Configuring USB port 'usb:/bus93/dev2/ (GretagMacbeth i1 Pro)' to 1 failed with -4 (No such device (it may have been disconnected)) Hi, what version of OS X are you running on ? Different profiling software recognizing instrument, and giving able to profiling. Could you provide some solution? My only thought is that the "other profiling software" is leaving something running, that is preventing the instrument from being opened ? (There is a problem like that with the ColorMunki that my driver has to work around.). One (laborious) way of determining whether this is the case would be to uninstall the "other profiling software". Graeme Gill. ---------------------------------------------------------------- Fiat, Seat, Ford - NOWE! Nawet kilkanaście tysięcy taniej!!! Sprawdź >> http://linkint.pl/f2902