On Mac's, openGL is specific to the machine production date and system update. Here's the link for Mac's
https://support.apple.com/en-us/HT202823
For Windows... Google it
You might find your graphics card is update-able.
When I first installed xyzware on SnowLeopard, graphics were crude. I updated to Yosemite and, wow! What a difference. I'm sure Windows will be about the same... I deleted xyzware on both my Mac's and Window's machines and just use Simplify3D.
Netfabb is both a Service and a stand-alone free app. You can download it from their site (it's called Netfabb Basic) http://www.netfabb.com/downloadcenter.php?basic=1 . That's what I use - it's much faster than repairing in Simplify (and does a better job).
Mac OSX ElCapitan
Prusa i3 (two built from kits), 1 hacked DaVinci
Solidworks for models, Netfabb to repair, Repetier/Slic3r and Simplify3D