NAV2016 crashes when opening new code editor

Hi all,

My NAV2016 environment has started crashing every time I try to open the code window in the Development Environment. If I change the startup to "useoldeditor = Yes", the old-style editor works fine.

I'm on CU2 of NAV2016. The event viewer shows 2 "error" events:

Faulting application name: finsql.exe, version: 9.0.42815.0, time stamp: 0x55f86e91
Faulting module name: KERNELBASE.dll, version: 6.3.9600.17055, time stamp: 0x532943a3
Exception code: 0xe0434352
Fault offset: 0x00011d4d
Faulting process id: 0x10ae4
Faulting application start time: 0x01d16e745dbc61b1
Faulting application path: C:\Program Files (x86)\Microsoft Dynamics NAV\90\RoleTailored Client\finsql.exe
Faulting module path: C:\Windows\SYSTEM32\KERNELBASE.dll
Report Id: a48cbeee-da67-11e5-80c5-1418772802e8
Faulting package full name: 
Faulting package-relative application ID: 

The second error does seem to point to the CodeEditor:

Application: finsql.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Reflection.ReflectionTypeLoadException
Stack:
   at System.Lazy`1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].CreateValue()
   at System.Lazy`1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].LazyInitValue()
   at System.Lazy`1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].get_Value()
   at Microsoft.Dynamics.Nav.Prod.CodeEditor.CodeViewModel..ctor()
   at Microsoft.Dynamics.Nav.Prod.CodeEditor.CodeEditor..ctor(IntPtr)
   at Microsoft.Dynamics.Nav.Prod.CodeEditor.CodeEditorFactory.CreateCodeEditor(IntPtr)
   at <Module>.CreateCodeEditor(Void*)
   at <Module>._WinMainCRTStartup()

I've been working in NAV2016 for several weeks now with no problem - then all of a sudden - crash!

Any ideas?

Ron