Rocket League requires components of the C++ packages in order to run properly.
The Microsoft Visual C++ 2010 SP1 Redistributable Package installs runtime components of Visual C++ Libraries required to run applications developed with Visual C++ 2010.
These files can be downloaded here:
**As of the Clubs Update on August 29, 2018, Rocket League will require the Visual C++ 2015 Redistributable. This should be downloaded and installed through Steam automatically, but can also be downloaded here: