So I don't really want to use Galaxy and don't care how big these games can get as offline installers.

Unfortunately, the installer for Dishonored 2 seems to be broken? The third file (setup_dishonored_2_1.77.9_(36134)-3.bin) doesn't pass the installer's integrity check. I've tried re-downloading the offending file, and then re-downloading the entire installer, and I still get this error regarding this exact file. I don't think this is a problem on my end.

I think it probably is, or it would be corrupt for everyone.
Try clearing your browser cache, or before re-downloading the offending file, rename it, and then change it back after it downloads.

You could check the BIN file's hash to see if it matches those from other users. I've been using wget (command-line tool) to download these since it checks for read errors and allows continuing more reliably than browsers.

Haven't installed GOG.com's version of D2 yet (still downloading the parts every so often) but my hash of that same file is the following (using the SHA-256 algorithm):

cfc7a0ced2d39aad11ffdde466c703f9224164bf6c92a2ca2378f243fc275d64

There are GUI-based checksum programs available but if one wants something already in Windows I made a command-line command that can be used to check.

for /f "delims= skip=1" %a in ('certutil -hashfile "setup_dishonored_2_1.77.9_(36134)-3.bin" SHA256 ^| find /V "CertUtil:"') do @echo off & set "h=%a" & echo | set /p=%h: =%| clip & @echo on

See the attached GIF for how to run this in the folder containing the file (only works in folder paths without special characters/Unicode).

The command uses the Windows in-built certificate utility tool ('certutil') to list a hash of the file using the SHA-256 algorithm. The 'for' loop skips the first unnecessary line of the output, then 'find /V' returns all text excluding the last line, leaving just the hash. The spaces are then trimmed and it copies the hash to the clipboard.

Process will take a minute or so before it completes for the large BIN files. Change the filename to whatever filename is in the directory (above looks for the '-3.bin' file).

The SHA-256 hash for the offline installer number 3 bin is CFC7A0CED2D39AAD11FFDDE466C703F9224164BF6C92A2CA2378F243FC275D64

But if it doesn't pass the verify test then it won't be right.

Are you shure the File is really -3.Bin, because the third file is the one with -2.Bin (the Starter-exe is 1 and then it starts with -1.Bin as 2). Just for being sure you dont replaced the wrong file...

Not the only one. It's happened to me twice now. It's a huge download (I also don't use Galaxy), and I'm busy with other things, so I was going to wait to see whether enough of the same complaints roll in for GOG to check the files on their end. I'm sorry that I can't be of any technical help to you, but I wanted to let you know that it's not just you.

I'm also seeing issues with Dishonored 2 3.bin and Death of the Outsider 3.bin.

Okay. That's three of us. Didn't know there was a similar problem with Death of the Outsider. Can't be a coincidence. Something to do with Denuvo's removal, perhaps? Dishonored 1 installs fine for me, and that originally only had Steam DRM.

Is GOG downloader even still a thing? I thought it was replaced by Galaxy.

My guess is that one or more of GOG's servers has a faulty file, or one or more of GOG's servers doesn't.

So, what are the correct file hashes for all the installer parts (including EXE)?

Did everyone's failing file have the same hash as pbaggers had? If so, then that would definitively point to a corrupt/incomplete file on some of GOG's CDNs.

Dishonored 2
setup_dishonored_2_1.77.9_(36134).exe
a4 d8 bf 31 65 91 ff 48 57 8e 3f 1a aa 5e 7e 1d df b3 21 e5 01 a1 29 6b 49 bf c3 ef 5d 18 f2 fe

setup_dishonored_2_1.77.9_(36134)-1.bin
99 ef 85 8e d6 93 b3 aa 2c d5 af 96 47 c1 4d 4e 64 7e fb 8a 07 01 98 14 4e eb 28 43 c4 e8 63 50

setup_dishonored_2_1.77.9_(36134)-2.bin
99 8e 81 4e 1d 08 6c 62 50 a7 02 c3 39 a0 46 9b 3c 04 97 37 f0 23 79 ed b0 87 45 d8 73 da 29 f9

setup_dishonored_2_1.77.9_(36134)-3.bin
cf c7 a0 ce d2 d3 9a ad 11 ff dd e4 66 c7 03 f9 22 41 64 bf 6c 92 a2 ca 23 78 f2 43 fc 27 5d 64

setup_dishonored_2_1.77.9_(36134)-4.bin
60 eb f9 8f b5 c5 0a dc d6 d1 46 16 80 be 08 9f 7b f6 a9 ca 1e ab b5 f2 93 46 d4 94 e4 a6 9a 02

setup_dishonored_2_1.77.9_(36134)-5.bin
d1 8b 22 ea a4 18 30 6e 28 96 7e f7 77 87 92 ae e3 10 c7 67 8e d6 01 43 70 89 a8 18 2a 11 15 5b

setup_dishonored_2_1.77.9_(36134)-6.bin
cb c9 cf ea 59 e2 dd 5b cb a3 55 b4 e7 57 a7 f7 b6 a4 e5 28 ec ff d0 23 7c 87 80 13 58 fa 0c 9d

setup_dishonored_2_1.77.9_(36134)-7.bin
d0 18 88 8d f1 72 2c a1 f9 49 22 96 bc 43 27 43 04 d7 60 e3 1b 7a 14 ab bf 36 2f 0e ca 61 94 26

setup_dishonored_2_1.77.9_(36134)-8.bin
92 d9 6a 78 19 f8 79 70 c3 8b a2 89 63 79 4d 5b d0 f9 48 b3 93 13 79 d7 19 40 67 f2 9d 6c 65 f5

setup_dishonored_2_1.77.9_(36134)-9.bin
d1 ab b7 cb 10 9c 5d 4f 8b ba 0e 23 73 51 d6 95 6c a6 76 4d 91 6b a3 5c 3c 30 d9 ad 0f a3 87 8b

setup_dishonored_2_1.77.9_(36134)-10.bin
09 65 7e 13 36 d0 4c 0d 6e 6a 11 13 c7 a3 bf 49 14 b1 b0 14 4e 5e d6 08 1f 89 6b d9 c1 96 91 f7

Death of the Outsider
setup_dishonored_death_of_the_outsider_1.145_(36134).exe
13 80 3c 0b ec 66 ea 64 89 e7 36 f6 26 ca aa 77 22 f9 97 fd 34 4e aa 6c 16 0b 9d db 2a d2 51 de

setup_dishonored_death_of_the_outsider_1.145_(36134)-1.bin
e0 ca 70 8e 01 65 4f 8c 09 c3 8e df 9e 29 3d 61 85 03 ff c5 62 9e 0c 46 1d 2e 5c d2 c9 80 37 7b

setup_dishonored_death_of_the_outsider_1.145_(36134)-2.bin
a9 ba 9f d0 24 5e d0 6d 67 83 02 8d 27 45 f1 b6 1b 1f 1d b1 98 5d 3f 78 15 f4 04 7c 10 7c b0 ce

setup_dishonored_death_of_the_outsider_1.145_(36134)-3.bin
e0 1d bd 8b 33 49 8b cb c4 1e 19 bd b5 3a 3c 2d 2a ab 70 24 35 25 2a 96 d5 a8 e8 52 d1 7a f8 8a

setup_dishonored_death_of_the_outsider_1.145_(36134)-4.bin
7f 9e 63 73 ea 20 22 fb 48 c1 d7 a7 06 0c 0d 03 45 1f ef 2a 42 5b bb a1 ef ee 39 c5 3e 56 e1 cc

setup_dishonored_death_of_the_outsider_1.145_(36134)-5.bin
6d 61 f8 85 96 66 41 c5 c5 49 7d ae 9f 6a 79 e2 7d 88 8a df 0a cc 88 af 17 ba aa 2d 9a b6 f2 a8

setup_dishonored_death_of_the_outsider_1.145_(36134)-6.bin
ac d9 80 b9 91 52 92 d1 06 57 50 fd 2b 05 18 f0 59 51 5c 9a ba 48 4c d7 2f 5a 33 00 7f 38 76 39

Useful, cheers. Also if anyone is comparing their own hashes which lack spaces they can ignore the spaces in them here since it's irrelevant (except for making it more readable at a glance).

I downloaded the installer through GOG Downloader and am pleased to say that it now passed the integrity check. I'll mark this thread as solved, but this is really an issue with one or more of GOG's CDNs.

EDIT: Death of the Outsider installs just fine too.