Here was my situation, plain and simple. Before I installed the Ultimate Upgrade 3 patch, I was running OFP version 1.29 beta. I had previously also been running OFP beta versions 1.27 and 1.26 before that. In addition, I had two major user addons installed in OFP: Kegety's Winter Kolgujev Island and Gunslinger's Editor Update version 1.2.
When I ran the Ultimate Upgrade 3 patch, I got some warning messages that the update didn't recognize OFP version 1.29 but I assumed that was OK since version 1.29 was a beta version. I noticed that the patch's execution to very little time.
I rebooted my computer (I always do that as a habit after updating Windows software) and decided to check things out. Some problems became apparent very soon:
So, I thought I would be smart and simply rerun the Ultimate Upgrade 3 patch again, in the hope that, now that OFP is at version 1.30 and not at a beta level, the patch would reinstall everything properly.
Nope. I got dozens of checksum errors when the patch verified my installation files. I had to hit IGNORE, when prompted to RETRY, ABORT or IGNORE each error.
Looking on the forums, I noticed several posts that hinted to similar problem or circumstances and, indeed, the only solution that seemed to be working was to fully reinstall OFP.
That's what I did and I was sure that my troubles were over. OFP wouldn't let me rest, though. When I started it, I got the ever-famous "Cannot create 3D device" message. I was about to faint but I remembered my own words of advice to run the OFP preferences program under these circumstances and click on the program's AUTODETECT button. I did and everything is just fine now, thank you. I've even restored the Winter Kolgujev Island and Gunslinger's Editor Update addons with no side effects.
If you're in a similar situation, I suggest that you follow my recipe for reinstalling. Better safe than sorry.