The first patch #1, which they withdrew because of the saved games problem, couldn't be installed with Galaxy because there was only 80 GB left on the disk (which should have been more than enough).
Then the fact they withdrew it broke the installation somehow, so in any case it's back to reinstalling everything, even with Galaxy

I think GOG is great, but maybe not so much for updates. For one, the patch notes are never available for new patches, we have to hunt them down on Steam
