How to show the menu in AutoCAD (3D PDF from AutoCAD) ?

How to show the menu in AutoCAD (3D PDF from AutoCAD) ?

Make sure AutoCAD is closed then please follow the steps in the pictures below:
1. Go to the %APPDATA% folder as shown:


2.  In the AppData folder, go to Autodesk -> AutoCAD 2016.



3. Search for the files containing the word "simlab" and delete them.






If this does not work, the do the following:

In AutoCAD, type "cuiunload", and press enter, a dialog should appear.

In the dialog, look for "SIMLABPDFAUTOCAD",

if the plugin does not exist, close the dialog, then type "cui" and press enter.

Another dialog should appear, click open, and choose the cuix file.