I knew that the jack itself was OK because it would work with the standard windows driver, but I could not figure out what was keeping the jack from being recognized with the Realtek driver.
Using the Realtek drivers, the headphones would not be recognized. Up until now, the only way that the headphone jack on my GS40 would work was if I used the base Windows HD audio drivers.
Forgive me if this has been posted before, but after fruitless searches, I had almost given up on being able to use headphones with the Realtek drivers for my MSI GS40 6QE and am excited to have found the simple solution for me.