Usual problems with DesignToolBox and how to fix them
Error opening 3ds Max
After reinstalling the or updating the tool, this annoying error can occur sometimes: 
It is caused by the ribbon interface. Some icon is missing, either because a problem with the installation or because was removed. To fix it the ribbon interface needs to be reset. Steps to do that:
- Right-click in the ribbon UI.
- Choose Ribbon configuration… Reset ribbon to default.
- Done.
Please note that if you made any customization or created a custom ribbon tab, and it is not saved and exported as a .xaml file, you will loose the changes. So please save and export your changes before resetting the ribbon.