Unable to open project due to c++ code


I created a project some time back in 4.16, and I had added a piece of code to the project to get the version number of the project and show it on a UI in the menu. That’s it.

Now, when I try to open my project in 4.18, I get the following error:

The following modules are missing or built with a different engine version:


Would you like to rebuild them now?

If I click yes, I get an error: Could not be compiled, try building from source manually.

If I click no, I cannot open my project.

How do I remove the c++ features from my project, returning it to a blueprint-only project?


I’m not sure how to undo the blueprint-to-C++ process but I can tell you that this happens all the time. You need to build the project from the Visual Studio solution. Once you get it built, you can migrate everything over to a blank project that is blueprint-only if you still want to remove the C++. If all you’re doing is calling one dinky function then I’d say the compile times are enough to go back to blueprints.

Hey, as the error message tell you to rebuild manually, try that ?

I will give you an error message mode detailed ( maybe you have a deprecated api call in your c++ code )

manual building mean with “visual studio code” or " visual studio community"

I recommande you to regenerate vs project before ( right click on Uproject file => “generate visual studio project files” )

Once you have the build error message, post it here so we can help you more !

i’m not sure you can go back to a blueprint only project ( would need a default editor dll, maybe by remplacing it but far from sur this would work )

Hey, I fixed it now using your suggestion to migrate the content… I copied all my assets to a new project, set up the inputs again, and assigned all the default game modes, characters, etc… and it all works again!

Glad to hear. And good luck with the next problem, there are always more in this line of work. :slight_smile:
If you could, please mark my answer as ‘the’ answer. It keeps the forum neat and gives me some ‘karma’.