What the hell is up with this client???
I am trying to update my bloody game for 4 hours now. I even resorted to uninstalling the GOG client and installing it again, just to see what's up. I restarted my PC like 3 times. And EVERY TIME I DOWNLOAD the 1 GB update it gets STUCK ON 99.9% (0.9MB left) AND THAT's IT . During the most recent attempt I waited around 10 minutes, just to see if something happens and the game randomly started and then, just as I loaded my last save - it crashed.

I am away during the work days and work during the weekends for 10 hours. This is the only time that I am able to play this lovely game, because my laptop cannot handle it. AND I WASTED MY PRECIOUS GAMING TIME, DEALING WITH THIS BLOODY BETA VERSION AND IT DOESNT EVEN ALLOW ME TO PLAY OFFLINE OR SOMETHING. It is a singleplayer game... *unintelligible screeching*

Don't use Galaxy. Browse to gog.com/account and download via your browser. You'll get all the files you need, and you can install them by hand (it's very easy; you just click on the executable and it does the rest).

Galaxy is nice when it works, I hear, but it's also nice to have a backup plan. Download via your browser. That's a good backup plan.

Thanks for the reply! However I just entered Gog's website and I see numerous links Witcher 3: Wild Hunt, The - Game Of the year edition (part x of 10) and they differ in size, but neither of them is 1,4GB (as Galaxy showed...)
Thanks in advance! :(

In the latest versions of windows, I see that many games have a tendency to get stuck in the final moments of installation (not only on Galaxy, mind you) because they're trying to install DirectX.

So I always ctrl+shift+esc and check the task manager for the DirectX setup and kill it, because it won't manage to finish on its own.

I'm not saying this is exactly the problem you're having, but if it ever happens again, it is worth checking out.

I really don't have an elegant solution. If you have a good enough connection, I would suggest you download everything, backup your saves, and uninstall Witcher3 then do a fresh install from the manually downloaded files.

If that's not an option for you (understand if you can't easily download another 30 GB) then maybe try what Falci suggested above?

Well now. Galaxy just decided that it's time for me to play some Witcher 3. For a few times I was able to start the game without even entering the client.
After an hour or so, I entered Galaxy intentionally and it showed me that the game is up-to-date and ready to play.
Curious.