Edit: Problem itself not exactly solved, just gave up and went with suggested alternatives in replies.

Hello, i have this problem where, i have been basically downloading Witcher 3 all day trough gog galaxy, i did the download trough More > Extras
I have been pausing the download every few gbs, and resuming somewhere under hour later due to .. reasons reasons i dont download such huge files all at one ago.
Anyway, after 20gb and something, i cant remember right now, if it was 23 or 26gb, anyway, i resumed download, went to do my own thing and when i come back, all i see is "failed" at the download, no other options to resume and such, i have been trying find a solution to make the download start again and continue from where it failed last time, made back up of the temp folder... where by the way i have no idea how much of it is downloaded and what are just ... reserve sorta files. cant tell difference from temp folder that i have been downloading for so long and fresh folder from new download, they both looks exactly same, taking same amount of memory.

- When i tried to do something simple like starting new download, then replacing new temp folder with old, it still keeps downloading from zero. Ugh-

How can i solve this without having to download this insane amount all over again? Thanks... i will keep looking for solution in the meantime.

I highly recommend gog downloader instead. Galaxy will be more stable on final release, now its in beta stages.

https://www.gog.com/downloader

Thanks for that. I sorta couldnt find it.

Still wonder if there is a way to... not have to redownload everything again?

Ugh, cant believe over 20gb of data is out the window... And downloading trough downloader, how does that work? There is no difference from galaxy i hope? i will still get achievements and ... galaxy library and all that? And everything is just the same? updating later and so on? I have no idea what so ever about anything. New to GoG, bought just Witcher 3 since it was on 50% sale.

After you have installed the game (downloaded with the GOG downloader) you can import it to GOG Galaxy (for achievements and so on). Here is a how-to:

== IMPORT ALREADY INSTALLED GAMES TO GALAXY ==

1. For GOG games installed using installers from the last few months (so called Galaxy-compatible installers)
Click the "+" button on top of the sidebar and select "scan and import folders" - it will find all compatible games within that folder and add them to the Client.

2. For remaining GOG game INSTALLATIONS
Find the game in the Library (click on the image of the game), then click the More button and select "Manage" -> "Import folder" and point the folder selector into the folder where that game is installed.
Please be aware that Client will accept any folder pointed to and will overwrite files inside it (this can for example wipe some mods or damage other apps in case of pointing to a wrong folder) and will update the game to the newest version (current default language English).

Source: http://www.gog.com/forum/general/gog_galaxy_beta_2/post1

Alright, thanks you guys. So, suppose that means i cant start now in evening, turn off pc some time later and then continue next day.. hm, alright. And after the download is done, do i basically have the game installer that i can put on dvd or whatever? not that i want, dont even have cdrom, i just like to have installers of games in case something went wrong and so on.
Thanks
Edit: Just viewed the attached pics, i see now.
Edit2: Also forgot to note before that im using avast, i think i noticed somewhere people talking about it causing mess in GoG Galaxy.

With big downloads, I usually pause it occasionally and put the PC into standby or hibernation. That way, I'm always able to resume the download later.
I think if you pause the process and then close the downloader via the "X" symbol (no logout that way), you can indeed turn the PC off entirely and still resume, but I'll have to check that.

As for your other question, you can basically do anything you want with the offline installers, including copying them to CD, DVD, external HDD, etc. to back them up. That's basically the core idea behind GOG.

EDIT: I was wrong about the "X" symbol. That just minimizes the program to the taskbar's system tray. What you have to do is pause the download, then right-click on the little downloader symbol symbol in the system tray and choose exit (see attached picture).
When you open the downloader the next time (via the desktop shortcut, for example), you'll still be logged in and the download will continue.
I'll now test this a bit further

EDIT #2: I just paused the download, exited the program and rebooted my PC. Afterwards, it still continued where it left off, so it seems to work, but I can't give any guarantees there.

Alright, thanks for the info! I have like one third to go now. Good to know i dont have to finish now.