From Conservapedia
String theory (or superstring theory when coupled with Supersymmetry) is a class of models in theoretical physics which replace zerodimensional points (particles) in fourdimensional spacetime with onedimensional strings in an elevendimensional spacetime as the fundamental building block of the universe. The main goal of string theory is to combine quantum mechanics and general relativity into a single, unified theory.
Counterexamples to String Theory show that it cannot be a correct method of determining why and how the universe behaves or came about:
 String theory has never been successfully used to generate a model of the universe resembling our own, with previously observed particles and forces in place.
 The idea of higher dimensional realms beyond 3 spatial dimensions and one of time has never been proven and is speculative at best, though there is hope that, if these theoretical dimensions are large enough, further tests with the Large Hadron Collider (LHC) could expose them.
 String theory cannot be tested due to the scale of the proposed strings^{[1]}, though elements of the theory (supersymmetry, extra dimensions, and the holographic principle) can be.^{[2]}
References
 ↑ "Tomorrow's Theories: Flaws With String Theory", The Nth Dimension
 ↑ "Can String Theory Be Tested?", PBS
Counterexamples 

 Counterexamples to:  
