I upgraded my Marketplace project to 4.11, but absolutely everything is externally referenced. I tried renaming the project folder, opening it, saving, closing, naming back, then opening again, but that didn’t fix the errors at all. Is there any other method to remove the external referencing errors?
You can try the config files. See here and links at the end.
That’s great for active class redirects, but this is an error with externally referenced packages.
I found that what worked best for upgrading my projects, was to just go into the project folder, right-click the .uproject file and select “Switch Unreal Engine version”.