Same here, i have GTX 660 and OBS v0.613b with latest nvidea beta drivers 337.50 and ShadowPlay 2.0. Tryed with 32 bit and 64 bit obs run as admin or non admin, still giving error. Switched on/off shadowplay from GeForce Experience same results.
Dammit. I am experiencing the same thing. Arrgh :( Going back to previous drivers is not a solution, since plenty of my games saw a significant performance boost with 337.50 on my GTX680. Isn't there *something* you guys can do to fix this issue with OBS? :(
I got it to work again by replacing the "nvEncodeAPI.dll" found in "C:\Windows\SysWOW64" with one of the previous versions of the dll file. You will need to boot in to Safe Mode to replace the file, also be sure to back up the dll file your replacing.
Please Note: For advance users only. Also note this is only a workaround.
Note 2: Previous versions of the dll can be found in "C:\Windows\System32\DriverStore\FileRepository" in folders named "nv_disp.inf_amd64_neutral_"