Apple released Unity Family Driver 2.5 for Logic Studio on Monday evening. The update addressed reliability issues when using the Unitor8, AMT8 and MT4 MIDI interfaces.
The update also addressed reliability issues when using multiple Unitor devices.
Unitor Family Driver 2.5 requires Mac OS X 10.5.7 or higher. It is available via the Software Update application, or as a downloadable installer at the Apple Support Web site.