Issue booting with nVidia proprietary driver

I have a Dell XPS 15 (2013) laptop with Optimus graphics (Intel 4600 + nVidia GeForce GT 750).

I can use the Nouveau driver just fine. It just seems a bit more unstable when I plug and unplug my exteal HDMI screen.

So, I usually use the proprietary driver from nVidia. The problem is that, since a few versions of the driver (about v. 346) onward, some of the versions work fine, but most of them fail to start. Whenever I update the driver, if it doesn't start, I have to uninstall the proprietary driver and go back to Nouveau until there is a new version.

I am not sure if the issue is in my system (currently ruing keel 4.6.0-040600-generic, GNOME 3.20, Ciamon 2.8.6), or if it is an issue of the nVidia driver.

Since my system moved to SystemD I am not too sure how to debug startup issues (which files to look at et al.).

Could anyone help me investigate why is the system not booting with some versions of the driver? Thanks.