There is a console error that pops up when loading a .blend file and every time un/maximizing a window (shift+space). After removing everything I could from the entire blend file, yet still getting the error, I noticed this small thing I did with my screen layout. After removing it, I found the problem (then I tested a little further to see where exactly it starts).

While [Source Engine Exportables] is open with the Scene tab open, upon the window reloading (I.E. load/un-maximize) a red error is sent in the console and info panel at the top.

The error occurs when [Cube] is not in the blender file.
There may be more to it but while the default cube is deleted, the error occurs, and upon adding the cube again, it stops.