I’d say this was already solved but my comments were too long for… well the comments section 
I ran into this same issue migrating some code from an existing project. This solution did work (thanks MajekPL)
The key turned out to be the uproject file (thanks Thorp) - I opened them up and was delighted to find they’re just JSON text files.
Failed to generate project files (blueprint project)
{
"FileVersion": 3,
"EngineAssociation": "",
"Category": "",
"Description": "",
"Plugins": [
//Blah blah blah (same)
]
}
Successfully generated project files (new C++ project)
{
"FileVersion": 3,
"EngineAssociation": "{DE101DE3-4830-ECCE-FBFD-8AAD629A2702}",
"Category": "",
"Description": "",
"Modules": [
{
"Name": "<MyModuleName>",
"Type": "Runtime",
"LoadingPhase": "Default"
}
],
"Plugins": [
//Blah blah blah (same)
]
}
Quick testing shows that the “EngineAssociation” is not necessary for generating project files and only the “Modules” section (makes sense).
So, potential quicker fix should be to add the “Modules” section to your .uproject once you have all the necessary C# and C++ stubs in place (which is probably most easily done by making a new empty project?).
"Modules": [
{
"Name": "<MyModuleName>",
"Type": "Runtime",
"LoadingPhase": "Default"
}
],