Apple Audio Extension 1.33 has allowed users of the Egosys U2A, Griffin iMic, Wave Terminal, and other USB audio interfaces to work with Pro Tools FREE. This extension is not a separately available component, but it is included with Mac OS 9.2.1. OS 9.2.1 also has a revised Sound Manager, but most users have reported success using the Apple Audio Extension 1.33 only.

At this time, the Roland UA-30, the Tascam US-428, the Tascam EZ-Bus, the Griffin iMic, and the Egosys U2A are compatible with PT FREE on the Mac using the drivers supplied with these devices and/or the new Apple Audio Extension above. Users are starting to report success with Emagic's USB I/O the EMI 2/6 as well.