For about two weeks I have the same error. It appeared out of nowhere.
I tried completely uninstalling the engine and .net framework (regularly as well as with the unofficial .net cleanup tool) and reinstalling both (first .net framework 4, 4.5 and 4.5.1, then UE4 4.5) like three times. I also tried the repair tool. Both without effect. “sfc scannow” didn’t help either.
My Swarm Agent uses the default settings.
I’m out of options. I don’t want to reinstall Windows just for this.