As posted some time ago i fixed some bugs in the Skin modifier in Max 2009-2011 using the SDK sample code. Mainly those two bugs ae fixed for Max 2009 (32/64bit), Max 2010/2011 ( 64 bit only )
* Max 2009 (32/64bit):
after working in Skin for a while, Max starts to crash when pressing the “Mirror Mode” button. This is some error that survives scene saves and Max restarts. So if the skin modifier got hit by this problem one time, the problem only can be repaired by exporting weight data and importing it on a fresh new skin modifier
* Max 2009/2010/2011 (x64bit only / D3D mode only, OGL works):
When activating “Mirror Mode” in Skin, the blue “dots/vertices” fail to display. Additionally display of selected vertices fails. There are other display glitches in mirror mode (please describe). And please tell specifically when you have this problem in Max2010 x64
Please download here and report problems/positive experiences with the package here in this thread
http://www.frogsinspace.at/?download=SkinFix_V1.0
Here is an image of the mirrored vertices fix