Just picked up my M8 the other day and tried htc sync manager with no luck. It just says no device connected. My pc is picking it up in device manager-other devices under 'android phone'. Ive tried putting the phone into debugging mode and still no difference. First android phone in a while and this is driving me bonkers. Have tried reinstalling sync manager many times and also updating the drivers for 'android phone' which it then says access is denied.