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I was working and all of a sudden heard my computer fan spinning extremely fast as if I was playing a 3D intensive game. I checked my processes and quickly discovered the culprit - mpch64.exe. My CPU had all cores at 100% except 1.
I was not running MPC at all prior to this, there were no windows open, it was as if it was running in the background. I checked for hard disk activity but it was negligible as far as any activity associated with mpch64.exe. Finally I killed the process.