We have fixed the problem where interfaces that also showed 3D graphics (Rapid Access/main window; side view) weren’t working correctly on Mac OS X 10.13 (High Sierra). The fix is in the current daily build and the very latest version of the 1.12 release candidate. If you get either of those then it will be safe to upgrade to High Sierra, at least as far as Chimera is concerned. ;-) —Eric Eric Pettersen UCSF Computer Graphics Lab