I attached the error message that appears when running the setup (or just check here). It states to run the installer's integrity check to verify which files need to be re-downloaded.

Well obviously that's not going to work with these new installers, I also checked the download page hoping to find a checksum for the files, no luck. So I'm not seeing a way to find out which files are corrupt so I can avoid wasting bandwidth and time, someone please point out I'm missing something and there's a way to check.

I've re-downloaded the setup file since it's small but it doesn't appear to be the bad one (unless it's corrupt on the server which I doubt).

What I would give for an simple .sfv file round about now.

Yay, editing the post seems to have removed the attachment, oh well.

Edit,, I thought I should clarify that when running the setup this error is the only thing that happens, the installer then exits.

Installer of big games that have .bin files still have an integrity check. For other installers you can check if the signature is intact.

This thread may be of interest:
http://www.gog.com/forum/general/gog_file_sizes_and_md5s/

I e-mailed GOG staff about this a couple of years ago when I first joined GOG. After several weeks of silence, they replied saying that according to them it is not necessary to provide the checksums info as their installer will verify the integrity. Obviously I did/do not agree with that, but that was their answer back then.

As far as I know the new installer checks it only before the installation (optionally), and only for big installs spilt over multiple files.
You can turn that on in installers that support it under Options, bottom left corner in the installer "main window".
EDIT: Oh and I think there are checksums that are posible to access via the GOG API. I tried out some 3rd party GOG downloaders the last few days and I think some said something about getting checksums fromk GOG.

Gabelvampir, unfortunately I couldn't find any option for it to check the files, the screenshot I showed was all that happened. Launch the setup, get error message, the end. Sorry I should have been more explicitly clear that nothing else happens there, after launching all that happens is that error message then it exits, so I don't see a way to get it to check which file/s are bad.

If you don't mind would you please point out these other applications you mentioned, I'd be interested in seeing where and how it gets this information, thanks.

I have to say I'm not in the least impressed by the direction the GOG installers are going, not just in this regard. Before they were acceptable, adequate, though lately the more I look at them the more bad design decision become apparent. Unfortunately that argument of theirs is only really valid with the old installer as the new one seems to just give an error message on execution then exit if it believes there's a bad file, unlike the old one which would check the files and name the file that's bad. (edit) Perhaps the new installer exiting and not naming the bad file only happens in certain situations or when corrupt in a certain way, since it happened without performing a checksum (end edit)

Though even then it's not a great argument as I'm not completely certain it listed all the bad files or just stops when it hits the first bad file. Which, if that's the case, means if one had multiple bad files they would have to run the installer to find the next bad file so they could redownload it, replace it, run the installer again, rinse and repeat for each bad file. So it seems like it's gone from okay-ish to worse unfortunately.

Sorry for not answering sooner, I was busy the last few days.
Could you perhaps repost your error screenshot? I did not see it before and you link leads to a 403 - Forbidden. I don't know if you can do anything if the installer starts with an error, but I'll try to look into that.
What game is this about? Maybe I have it per chance and could post the md5s of my files.

Statements like this are useless to folks like me who just play these games and are not computer wizards. I've recently developed problems with The Witcher, a game I bought a year ago and have played through a few times since with a few minor but not serious issues of it crashing for no reason on occassion. I noticed recently, however, that when I went to save a game or load a saved game that it took longer and longer and the game would sometimes crash when I tried to save a game. Finally, I started the game one evening, went to the launch page, clicked the "Load Save: button and the game instantly crashed. Tried it again and it crashed over and over the second I clicked on the load save button. Windows spontaneously checked for why it crashed and flashed up on my screen this error message:

"The source file is corrupted"

"You should run the installer's integrity check to verify which files need to be re-downloaded."

I haven't a clue what a "source file" is let alone how it could become corrupted after a year+ of playing the game. I ASSUMED the source file had something to do with what I downloaded from GOG.com. I searched "installer integrity check" in "microsoft help" to see if it would tell me what it meant and it took me to ScanDisk. I then ran scandisk (as "help" prompted me to) to verify I didn't have some corrupted sector of my hard drive or a sector that went dead for some reason and thus caused the problem. My hard drive checked out perfectly fine. I then did a diagnostics on my RAM to make sure all my mempry was intact and it too was fine.

That left me thinking that SOMEHOW the game I'd been playing for a year+ must have had a file or two I downloaded from Gog.com go bad for some unknown reason. I went to GOG.com to see if there was a search engine there or something that could tell me if this mysterious thing called an "installer's integrity check" was some kind of tool or utility I could just click on which would then check my program and see if and where and what file of The Witcher was corrupted and just fix it or let me download uncorrupted files.

OH IF ONLY I could be so lucky. GOG.COM didn't even have a search engine that I could use to find what an "installer's integrity check" was let alone have any "tool" I could use.

So I tried re-downloading The Witcher from Gog.com, figuring that would patch over and correct any corrupted file. It didn't. The game continued to crash the instant I clicked on the "load save" button.

So I uninstalled The Witcher. As the uninstall was about to execute it asked if I wanted to save my saved games. I clicked "yes" then uninstalled and went back to GOG>com and re-downloaded the game a second time. Then I went to launch it and - NOPE still crashed the instant I clicked the "Load Save" button and it gave the same error message.

So I uninstalled it again, this time erasing any and all vestiges of the Wtcher from my computer, including all my saved games, because I figured maybe the corrupted files are in the saved games portion of the Witcher. Then I re-downloaded it a 3rd time from GOG.com, completely fresh ... went through the entire installation process, launched the game, it went through all the preliminary stuff as usual and then I tried to start a new game from the startup/load saved game page. It crashed the second I clicked the "start a new game" button, which was a new problem because prior to that I could at least click on a new game and it would take me inside the game. The problem was, I couldn't save anything in the new game because if I did it would crash the game. I got the same exact error message!

All I wanted was to get this error or corrupt file fixed and there is ZERO help or resources on GOG.com to get help. There is no help file to explain what an "installer's integrity check is" let alone how to use it. After reading through this forum it seems GOG.com doesn't have an installer's integrity check and in fact removed them from their installer! So does that mean The Witcher is now inaccesible?

So Gabelvampir, saying things like some big games have .bin files that still have integrity checks in their installers DOESN'T HELP ANYONE. HOW do you get to the installer's integrity check to have it do the check and how do you find out if your game has .bin files (whatever the heck .bin files are)? Assuming I found I had .bin files how would I access and use the installer's integrity check. Assuming it found the corrupted files, how would I download uncorrupted files to replace the corrupted ones?

And then to say "for other installers you can check to see if the signature is intact" What the heck is a signature and how do you check it? And how would checking the signature FIX the corrupted files?

I've scoured the forum for help, even went to the link provided by Snickersnack and it was all written in ancient Sumerian Cunieform to me, (they assuming us readers would ALL know what the heck they were talking about). I eventually ended up a GOGWiki where it was supposed to have integrity checks for installers for the games and ... well ... I couldn't find anything even remotely related. If it is there it is about as obvious as a needle in a haystack.

As you can see, I am quite frustrated and I'm asking if there is anyone here that can actually help with this. I've sent a support request to GOg.com but as of yet there has been no response.

I think you are misunderstanding what has been written here already, though the posts do assume some knowledge of Windows and GOG installers, so I've put the details here in as user friendly a way as I can.


For the GOG installers, if you have a small game it will be one executable file (that is a file that runs as a program that installs the game). The GOG installers have filenames such as:

setup_duke3d_2.0.0.85.exe

(I highly recommend that have file extensions shown so that the .exe is visible).

For these single file installers, to verify that they are correct and not corrupted from a broken download or such, you have to check their Digital Signature. To do this in Vista and Win7 (I've not used Win8 but I'd imagine it is the same) you right-click on the executable file and select Properties. In the Properties window there is a tab called "Digital Signatures". There should be one for GOG Limited. Select it and press the Details button. A window should then appear telling you whether or not the signature is OK. If it is OK then the file is good. If it isn't you need to redownload it.

The only downside I can see for the use of Digital Signatures is that they will eventually expire (each one has an expiry date). So good files will eventually show an out of date signature.


Next are the large games. These are multi-file installers consisiting of one executable file (.exe) and one or more binary data files (.bin). For example:

setup_ut2004_2.0.0.6.exe
setup_ut2004_2.0.0.6-1.bin
setup_ut2004_2.0.0.6-2.bin

You can still check the Digital Signature of the .exe file but that only tells you if the main executable file is okay, and not the binary data files.

To test the installer files in these cases you have to run the main executable file (e.g. setup_ut2004_2.0.0.6.exe). When it runs, press the Options button to view the Installation options. The option to "Check files integrity before installation" can be used to run the File Integrity Check which tests all of the files and tells you which ones (if any) need to be re-downloaded.

Note: It is highly recommended to run GOG installers with administrator access (right-click on the executable and select "Run as administrator").


Hope this helps.

I am sorry I did not explain it to you more clearly, I thought the statement that the intergrity check can be turned on under options (for games that have an integrity check in the installer).
And you never stated before that you mainly have a (save game) problem with The Witcher. For fixing your Witcher problem best PM JudasIscariot or wait for support to write you back).
For future use read korell's explanation, it is written to be easy to understand in my oppinion. And you don't have to be a "computer wizard" to do this, you must simply be able to read an click buttons.

Nevermind, old message which was answered already.

Damn it guys, so many necromancers in just one thread! :P

What do I learn of this? Look closer on trhe dates of the thread and don't answer to people who complain to you about helping other people with other problems over a year ago.