Atik460 Nebulosity 4 on OSX - no exposure over 2.4s possible

[physicus]

Has anyone had this problem; seems so weird ?  Brand new 460 - fantastic.  But, capturing in Stark Labs Nebulosity native OSX version on both a 2009 MBP and 2012 Mini, setting any exposure over 2.4 seconds (pretty much exactly as far as I can tell) for preview or capture produces a black image and no capture.  This has forced me to fire up an ancient WIn95 on Bootcamp on the MBP with Atik's Artemis, just to convince myself the camera is okay - which it is.  Also, the Windows version of Nebulosity 4 works fine too.  I only bench tested the 460 when it arrived with a 0.01 second exposure during the day, so I only discovered all this of course in the middle of last night !  Stark Labs site say there are outstanding Atik problems for Mac, so I guess this is one of 'em.  With a Windows version of PhD downloaded I should at least be in business again - however reluctantly back in Microsoft land.