I am mainly working in Maya2016 but installed 2017 to check out Arnold. The rendersettings in 2016 could not be opened from there on and I got a error with the RenderGlobals (when I remember correctly). Resetting the prefs and even reinstalling it did not help. I uninstalled both versions and deleted all Maya folders left on the system, then intsalled 2016 again and it works correctly now. I always had problems installing multiple Maya versions on one system. Why is that? In school there are multiple versions as well (Networklicenses I guess), so I guess it should be possible in theory.
