MPC touch Problem!! Disconnect automatically!!!!

I bought a MPC touch the day before yesterday, and I found a problem is that it will disconnect the mac(10.10.5 yosemite) automatically without any foreboding! Suddenly!!
I tried to pull out the usb cable and plug it back , it's no working. The only way to reconnect is press the POWER in MPC touch, off and on.

should I return it or it's a software problem can wait for the next updates?

It might be an Apple issue.

It's not a known problem with the Touch or Yosemite (as far as I'm aware), there's plenty of happy 10.10 Touch users. Could be a hardware issues (Touch or Mac USB port), software conflict in your Mac, or maybe your Touch drivers are corrupt. First step is to perform a complete uninstall of all MPC related software (drivers, application etc), reboot and reinstall from the latest installer.