But when they pirate the game it is not their own copy they are downloading. They are not entitled to THAT download.

It doesn't matter if the copy they 'pirate' are not theirs. What they're 'pirating' is the same bunch of zeroes and ones that forms the original copy, sometimes with a crack depending on the DRM in question. And if that is still a problem, perhaps because the support team might ask about the authenticity of the game copy, you can still convert the 'pirated' copy into a regular copy by letting GOG Galaxy know that this version of Witcher 3 is downloaded and then ordering it to repair or verify the game data, thus converting it to 'their own copy', as I said before. Since they own the game, that shouldn't pose anything on them.

Either way, I'm also looking that I solve the OP's problem in the most legit method possible. Perhaps I could see the problems with my own eyes using TeamViewer, but that's if the OP allows for me to view the desktop for a fix. I wish the OP sees my Free Download Manager method.

But it is still an illegal copy whether your want to try get round it or not. You're still taking someone else's copy from a website that is very likely banned in so many countries for a reason. But saying that, this kind of thing shouldn't have to happen because GOG is perfect.

And where did that someone else get their copy from? Sometimes it might be the same download the OP is unable to finish, from GOG. By that logic, I can't give a friend the installer of Witcher 2 from GOG in an already downloaded form, even if we both own the Witcher 2 on GOG, because its my copy and not his, even though there are no strings in the installer saying this installer belongs to PookaMustard and none else or whatever. I'm not playing with DRM'd installers here. And I'm not sure how torrent websites are banned in so many countries. They're supposed to be everywhere. Again, 'this someone else's copy' can be converted to 'yours' easily. What matters is that the OP already owns the game on GOG. I'm not saying that they should torrent all their owned games from now on, but I'm saying I don't see what is wrong in that versus outright pirating the game without owning it legally.

It's not immoral. It's still piracy - if nothing else, with torrent you also upload to other people who maybe bought it, but more likely not. And you still risk getting "superior" content - all the malware that GoG "forgot to bundle". Doing it with legally bought drm free game indeed feels head-desk worthy.

For what it's worth, I never encountered corrupted download with gog, for the whole time I was using browser, gog downloader, lgogdownloader and Galaxy. There is good chance the problems are with OP's ISP or computer.

Country dependent actually. You are claiming that if you buy a game on GOG that I also have and I give you a copy of it on a DVD, you are committing piracy. GOG themselves have suggested that method of gifting games in the past, since you could make a lovely DVD case with the games (and include a gift code with them of course).

The possible illegal part is the uploading the torrents do, not the downloading. But check with a lawyer in your country to be certain.

Whenever I can't start my car, I always just take the nearest car that is almost identical to the one I have.

On a more serious note, try GOGRepo or LGogdownloader (if you're on Linux).
Anything created by the community is usually 100x better than what the team at GOG produces.

Not a bad idea, and one supported by Humble. Could be a pretty good option for the bigger and more popular games such as The Witcher 3, that are probably being constantly downloaded.

sounds like you have a really unstable internet connection or seriously bad ping to get a checksum error. ring up your ISP.

oh , and if your connection is really that bad( and you're not a very lame troll), downloading from piratebay or any other alternative will NOT improve your download experience.

the GOG downloader already works like a torrent client anyway, using multi-stream downloads. a torrent client that's connected to one of the faster software servers on the internet. you're not gonna get better speeds or stability from random seeders or buccaneers, who tend to be quite limited in bandwidth allowance compared to GOG.

And downloading GOG installers from the net instead of GOG servers may or may not be piracy. It depends on whether you own the game on GOG, on whether your country views downloading copyrighted material you have the right to access as piracy, and whether you are downloading or uploading as well.

Torrenting a game does not necessarily mean you are pirating said game, weird as it may sound.

I can't help but notice you're not disputing the second part of the statement.. :P

Malware depends on whether the torrent is reputable enough or not. Usually you'll be able to see it in the comments by the time you think of torrenting to begin with. As for uploading to other people, I think you simply limit the upload rate to something that is so 90s, e.g. 1kbs. Nobody will feel like thanking you for a couple of small kilobytes.

I never use the client as I see no point in it at all.

Steam, direct downloads, 'other' downloads = never any problems

The second I use GOG my ISP has problems apparently lol. Maybe the problem isn't me and their servers are just terrible?