Hi Takahiro -
Please try to remove the preferences file for Rhino 6. This page describes where you can find that plist. I would not delete it but move it to a different place (e.g. your desktop) so that, if necessary, we could try to see why this plist causes Rhino to crash.
-wim
I tried moving and deleting plist together, but still the situation did not change.
The files in the following paths were moved/deleted and then reinstalled, but still would not start.
Macintosh HD/Applications/Rhinoceros
Macintosh HD/Users/“Username”/Library/Application Support/McNeel
Macintosh HD/Users/“Username”/Library/Preferences/com.mcneel.rhinoceros.plist
Macintosh HD/Library/Application Support/McNeel