Did you fix your problem ? I had the same issue this week and decided to run the installer again on my external drive so I can see what could be the dependencies, and these are:
- DirectX
- Microsoft Visual C++ 2015 Runtime
- .NET Core 3.1
If you carry these installs on your external drive for future "move to another machine", these need to be installed on the machine to launch Launchbox properly.
At least for me, it did the trick.