As mentioned at the bottom of the Avatron site
The Air Display host software runs well on Lion, but has this limitation: the built-in video driver on certain 2008 and 2009 Macs is incompatible with third-party video drivers. You can still install the Air Display host software, but until Apple fixes the issue, the Air Display drivers will disable themselves on Lion on these specific machines.
Affected machines include:
- 13" MacBook (aluminum late 2008, early, mid, and late 2009)
- 13" MacBook Air (late 2008, mid 2009)
- 13" MacBook Pro (mid 2009)
- 15" MacBook Pro (late 2008, 2.53 GHz mid 2009, mid 2009)
- 17" MacBook Pro (early and mid 2009).
- 20" iMac (early or mid 2009)
- 24" iMac (early 2009)
- 21.5" iMac (late 2009)
- Mac mini (early or late 2009, Server late 2009)
- Mac mini Mac OS X Server (late 2009)
Apple is aware of the bug. We are hopeful that they will release a fix soon.
