Issue:
When opening a file or intermittently while working in AutoCAD, the program crashes with an unhandled exception error in the mc3.dll or mc3d.dll files, such as the following:
Exception in mc3.dll / mc3d.dll ARX Command
Unhandled Exception C0000005 (Access Violation Reading 0x0000)
Causes:
Damaged WHITELIST.XML file, specifically affecting AutoCAD Architecture 2016 and AutoCAD MEP 2016.
Solution:
To fix the crash for AutoCAD MEP 2016 and AutoCAD Architecture 2016:
Exit all Autodesk programs.
Navigate to the following folder:
For AutoCAD Architecture 2016:
C:\Users\<user>\AppData\Roaming\Autodesk\ARCHDESK\2016\{5783F2D7-F004-0409-2102- 0060B0CE6BBA}\7.8.44.0\MC3
For AutoCAD MEP 2016:
C:\Users\<user>\AppData\Roaming\Autodesk\BLDSYS\2016\{5783F2D7-F006-0409-2102-0060B0CE6BBA}\7.8.44.0\MC3
Delete the file WHITELIST.XML.
Restart the computer.