FATAL ERROR [2018-09-07 16:50:04Z]: Visual Studio failed to start. Some of the assemblies required to run Visual Studio (for example gtk-sharp)may not be properly installed in the GAC.
System.NullReferenceException: Object reference not set to an instance of an object
 at Mono.TextEditor.TextViewMargin+TextViewMarginAccessibilityProxy.GetRangeForLine (System.Int32 lineNo) [0x00013] in /Users/jason/src/monodevelop/main/src/addins/MonoDevelop.SourceEditor2/Mono.TextEditor/Gui/TextViewMargin.cs:242
 at (wrapper delegate-invoke) System.Func`2[System.Int32,MonoDevelop.Components.AtkCocoaHelper.AtkCocoa+Range].invoke_TResult_T(int)
 at MonoDevelop.Components.AtkCocoaHelper.RealAccessibilityElementNavigableStaticTextProxy.AccessibilityRangeForLine (System.nint line) [0x00001] in /Users/jason/src/monodevelop/main/src/core/MonoDevelop.Ide/MonoDevelop.Components.AtkCocoaHelper/AtkCocoaHelperMac.cs:1572