Project suddenly takes long to load and when pressing play in editor everything Freezes. Why?

Hello everyone,
I have an issue with starting my project, everytime I do that it takes about an hour to start. I have to admit that the size of my Level is quiet big so it is not that surprising that it takes a little bit of time. But I heavily doubt that this is causing the long time, since yesterday everything worked relatively smooth. I think it has something to do with the Kite Demo I added to my project yesterday because since then it loads really long and does not start when I press play in editor (Instead everhing just freezes). I already deleted all the folders of the Demo, but that Problem still existed. So I copied the project and deleted the Save and Intermediate Folders, because in another post it was said that this might help. Well it didn’t. In one post it was said that at 93% (Where it is always stuck loading) the engine is loading the Blueprints. My assumption is that some files of the Kite demo have not been deleted properly and are now delaying everything.
So my question is: Is that possible? If yes what can I do about it. And if not what else might be the Problem?
Thanks in advance:)

I solved that problem by replacing my map file with an autosave file. When looking at the size of my the different autosave files, I was surprised that there was a point (Yesterday) at which the size of the files doubled for no reason. Maybe it helps somone else.