Digidesign has documented issues with new MacBook and MacBookPro intel-based laptops where USB interfaces like the MBox and MBox2 don't work well when connected to the right-side USB port . Connecting the MBox to the left-side USB port of the MacBook often works better.

Posting at www.digidesign.com
• Compatibility Alert •
Use of Mbox 2, Mbox 2 Mini, Original Mbox, or Other USB Audio Devices on the Right-Hand USB Port Is Not Recommended
The 15" MacBook Pro models have 1 USB port on the left side, and one USB port on the right side.
The 17" MacBook Pro models have 2 USB ports on the left side, and one USB port on the right side.
Due to internal USB architecture issues on the MacBook Pro, use of Digidesign, M-Audio, or third-party USB audio devices is supported on the left-hand USB ports only (the port or ports next to the power adapter cable).
Use of such devices on the right-hand USB port is not advised because it may cause audio interrupts and/or dropped samples.
However, the use of an iLok on the right-hand port has been qualified and is fully supported.