Design Assistant not showing up
@Anonymous
It sounds like Inventor is not properly registered with the OS
Use the following steps to re-register Autodesk Inventor with your operating system:
1. Exit Inventor if still running
2a. Win 8/8.1/10: Select the Windows start button and type CMD (but do not hit an enter)
2b. Win 7: Select the Windows start button and type CMD in the search field (but do not hit an enter)
3. When CMD or command prompt appears in the list, right mouse click and select run as admin
4. When the command prompt appears, navigate using dos commands to C:\Program Files\Autodesk\Inventor <version>\Bin or where your Inventor.exe is located if you changed the default install location of Inventor.
In this example I'm navigated to my Inventor 2018 (exe) location.
6. Type Inventor.exe /install.
Wait a few mins and restart Inventor. At this time you will not see anything occurring. Don't panic. 
However if you launch Windows task manager you can watch the Inventor.exe process (and see when it ends).
Does that resolve the issue?
Mark Lancaster
& Autodesk Services MarketPlace Provider
Autodesk Inventor Certified Professional & not an Autodesk Employee
Likes is much appreciated if the information I have shared is helpful to you and/or others
Did this resolve your issue? Please accept it "As a Solution" so others may benefit from it.
Might be related to their User Account Control settings, see the following.
Thanks,
Danny
Danny Hubbard
QA Analyst
Autodesk, Inc.
