There seems to be an issue with OSMC. I previously was running RaspBMC on a rPi1 and just upgraded to a rPi2 and installed OSMC. Whenever I would plug in a USB flash drive it would constantly mount and unmount. I never had a problem with the rPi1 with RaspBMC using the same 2.4A iPad power supply. I just installed OpenELEC on the rPi2 and the issue has disappeared. This leads me to believe the issue lies with OSMC.
It’s a power supply issue.
OSMC uses more power than OpenELEC
Sam
Do not use an iPad charger, they are not compatible with the Raspberry Pi as the voltage drops as low as 4.3 volts under load. This will cause USB devices to fail.
Use a known good power adaptor recommended for the Raspberry Pi, such as this one: