Thanks.
I had the issue before in another PC, but I cannot seem to solve it on my current one, which is also quite different from yours. I had not played since that previous PC, so I did not find out until I started testing now that it also errored out in this one.
I tried several more things yesterday, but today I woke up to a COUNTRYWIDE power blackout :/ No idea yet when we'll have power again.
Since I had the time yesterday, I did this so far: I used an HDD I had laying around (checked to be perfectly fine) for a clean Win 10 Pro 1803 install, kept it offline, and the only way in which the error did not occur was while running the system on the MS basic video driver (which bugged the shit out in many other ways, obviously). As soon as I installed the latest NVidia drivers (for my 1080), it errored out again. Tried all of the NVidia control center options more or less one at a time, just in case, and of course running the game with 3D acceleration completely off from the game config... Nothing worked.
I recorded all the files the game was writing to, and there is no correlation with the errors.
Also tried disabling every advanced processor option I could in the Bios (Asus Maximum VIII Hero Alpha), hyperthreading, virtualization, etc. No difference. Also with the RAM (4 sticks of 8Gb Corsair 3200Mhz DDR4), I left one stick in, and ran it at standard speed (not even XMP profile).
So, going back to the drivers, I say "Progress!" and tried with enabling only the integrated video from my i7 (HD 530), which was completely disabled before (not even in multi monitor mode). Did not use the disc image taken right after Win 10 was installed, that I was using to keep things clean while trying different options and drivers, but installed from scratch again. Installed DCH Intel drivers, and... Same error.
Will try with different Win 10 versions when I can. But I'm starting to think this is a matter for GOG's support to handle. I simply cannot understand how there are not more reports on this if it happens on such different hardware. Searching online only shows a couple of reports in forums, and they went unanswered.
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vsr: Probably worth a try to install older vcredist.exe file.
You can find it bundled with some older games or download it from somewhere.
Thanks, already tried. But will investigate more on the version of the files needed by BG2 and try and get the closest to those as possible.