Is there any way to disable the automatic monitoring of directories and importing assets? It’s certainly a great way to crash Unity reliably, but it’s getting out of hand. 
Also, did something change along those lines? My max files now appear in Unity with a different Icon, and they are not as easy to import or configure. Only when I export to FBX do I get the usual cube icon and settings.
Thanks in advance for any help. 
Not individual directories, but there is an AutoRefresh option in the preferences which can disable it altogether.
It sounds as if either Max is not installed on that machine, or Unity is having an issue running Max in the background to export to FBX itself.
I bet it’s because I just installed a trial version of 2012, but have multiple licenses of Max on here. File associations were probably changed causing Unity to try and use a different Max than what I actually work with (2011).
Over the last few years Autodesk has dropped the ball with their software. The max process that hangs around in the background (thanks to Unity) has always given me problems (slow machine, memory leaks, etc). I used to blame it on Unity (I disagree with the idea of directory monitoring and autoimport to begin with), but I’d bet this was probably Max all along and not Unity at all.
Turning off Auto-refresh should be exactly what I need, considering I prefer to control each import by hand anyway.
Thank you very much for your reply!
I would really like to disable auto import as well, but only for 3rd party 3D application files like MB, BLEND and LWO.
Please consider up voting this Unity feedback so we might get this feature in the future
https://feedback.unity3d.com/suggestions/per-folder-import-ignore-list