Our team recently moved to the master branch of 4.12 and we are still getting a “Files need check-out” bug where anywhere from 25 to 50 or more of these types of pop-up messages appear when certain blueprints are compiled. Usually it tends to be a bigger issue with blueprints that have more references. This issue always happens on compile and not on save. I’m guessing that the engine wants the other classes which are referenced to be compiled and checked out with whatever blueprint is being edited. This is a usability issue for a few reasons. For one, it disrupts team workflow where another team member may already be working on a blueprint which is in the list of references. This issue is also problematic because it basically ceases work for the number of seconds it takes for the cascade to stop. Couldn’t a bandaid solution at least be to negate the message being called if one is already on screen? Only one needs to appear, not 50 or more. This prevents the user from even editing the blueprint or continuing work because the messages take up the entire right side of the screen. Also, clicking on the “Check out” button generally doesn’t do anything in these cases. Only about 5% of the time clicking on “Check out” will find the correct references and allow me to check them out.
I’m sure that starting a fresh project and creating and editing a few blueprints would not be a problem. We have been working on this project (since porting from UDK) since Unreal 4 was released, so we are definitely working with an “older” codebase.