OBS is crashing due to outdated Elgato's drivers. Follow these steps (carefully, in order!) to correct it.
1) Unplug your Elgato device (if USB)
2) Uninstall all Elgato software and drivers from Add/Remove Programs
3) Reboot your PC (Very important you do this before trying to install anything else)
4) Reinstall the Elgato software/drivers (make sure to download the latest)
5) Plug the Elgato card back in (if not already prompted to during the Elgato software installation)