Q: "My MBox 2 powers off or loses communication with ProTools when I enable phantom power. The Mbox 2 is connected to an Apple Powerbook."
A: Phantom power should only be engaged after the Mbox 2 is connected and Pro Tools is launched. If phantom power is on when the Mbox 2 is first connected to the CPU, it will drop offline. So in these cases, the following steps are encouraged:
1. Connect the Mbox 2 to the USB port with PHANTOM POWER OFF
2. Launch Pro Tools
3. Connect any phantom-powered microphones
4. Turn phantom power on
These steps should keep the Mbox 2 online.
This issue is normally isolated to specific PowerBook models. Detailed information can be found at http://www.digidesign.com/compato/osx/mbox2/pb.cfm