See attached image.

WHY?!?!

Even the patches were doing this before I uninstalled and tried installing fresh. WWWHHHYYY?!?!?!?!?!

I was able to download & install the both offline 3.02 patch and the offline 3.02 full installer. Have you tried that instead of using Galaxy?

Same thing happened to me. I reported it to GOG but have yet to receive a response. I used the standalone patch and it worked with the Galaxy install. Unfortunately Galaxy still wants to patch the game even though it's on the latest version.

Same thing to me when Galaxy finish the installation, it turn in loop (100%..100,1% weird) but the game seem to work

I'm getting the same thing, it went to patch, and runs over 100% then fails saying that there is a connection error. Retry, same process of ticking up from after 100% and then connection error. Game is not installed so I cannot launch it (this was on a reinstall attempt as previously Galaxy was reporting the game was corrupt).

I have got the same error when I am trying to instal the game, saying connection error.. Right now i have downloaded 7.6GB/7.5GB.. I have no idea how it is possible.. I Tried to uninstall and download again but still same error.. I got this error only on my PC with windows 7, while on my laptop with w10 there was no problem at all.. Any ideas how to download/install it correctly?
Thank you in advance.

Have you tried using the offline patch and/or installer instead?

hmm I was not there for a while and now it is installed normally. Interesting.. I tried it for 2 days and nothing. thank you anyway

Same issue here. Dont know what to do. Repair bottond doesnt seems to work.

Download the offline installer and reinstall the game over your previous installation, it worked for me.