The new Apple Mac OS X Lion (10.7) is now available for download from the Mac App Store. However, please note that at this time Pro Tools 9, including Pro Tools HD 9 and Pro Tools MP 9 and all earlier versions of the software are not compatible with Mac OS X Lion.
Pro Tools SE software, which is bundled with select M-Audio products, is fully qualified for Mac OS X Lion once you download and install a patch. The patch is available via Pro Tools auto-updater, which will locate the update for download and installation (less than a megabyte).