This problem came up for an existing project after I started adding classes based on UE tutorial videos. If I start a new project, create a class (the command New C++ class), it will auto compile, I modify nothing else in any way, reopen the project this error is there as well (The game module x could not be found). I cannot get into these projects in any way. I have searched for solutions and people suggest you need to externally compile it or clean the intermediate folder. I confirmed these don’t work. The module that it cant find seems to be there, UE4Editor-MyProject3-1060.dll. It compiled correctly. I can;t seem to find any log or way to see more information. I actually did try reinstalling UE4.20.1 and Visual Studio.
Update: I am able to open previously un-openable projects buy opening them in visual studio, using the clean command, and then opening the unreal project. This will recompile the dll from scratch and it appears to work normally. I still believe this is a bug as described in the OP because I was able to reproduce it with a new project even with a fresh install.
Same issue here, just create a new plugin and then can not open project anymore 4.20.2
Please follow this document as below:
Your project might get rebirth.
At least I solved