2009 Mac Pro randomly waking up from sleep

[rolandlim]

I have a 2009 8 cores 2.66Ghz Mac Pro with 16GB RAM and ATI Radeon HD 4870. It keeps waking up randomly from sleep. I have tried quitting all applications before sleeping, but it still woke up from sleep by itself. Anyone has nay idea why it kept waking up randomly?

 

[Dreamail]

Usb

Check your USB devices.

Could it be that you're plugging/unplugging a new device? Perhaps a loose connection or faulty cable that 'simulates' plugging/unplugging?
If you have a USB mouse or keyboard and disconnect it, the Mac Pro will wake from sleep as it tries to mount/unmount the USB device.