I am having the exact same problem. And I tried pretty much the same thing to fix it. I am running a 2012 version of Adobe Camera Raw on a mid-2009 MacPro with a 4 core Nehalem processor, 16 GB RAM and a 2 processor Nvidia GTX 680 with 2 GB VRAM. I am running OS X version 10.10 (Yosemite).
I finally got a cryptic error message during a "forced" install that said my system was outdated and needed to be upgraded. ACR now only works on OS X version 10.11 and beyond. On Windows, you need to be running Windows 10 with the "Creative" update from August 2017 to be able to install this update. This appears to be a trend across several apps with this latest Adobe CC update. So far, on the other forums, there seems to be little concern on the part of Adobe about fixing this problem. Good luck!!
According to a Google search, my video card seems to still be worth $500-$600. Maybe I can sell it and buy another year of Adobe Creative Cloud...that no longer works on my system.