Hello, I've tried installing SOMA manually by downloading the 4 required files through both Firefox and Chrome. As suggested in another help thread on integrity failure check.

I would rather not use Gog Galaxy as I prefer to have as few background programs running as possible. Has anyone got any tips on how to proceed? Thank you for your help. :)

Hi :)

'setup_soma_1.61_(64bit)_(50360)-1.bin' and 'setup_soma_1.61_(64bit)_(50360)-2.bin' are only 8MB instead of 4GB.
We'll have to wait for the files to be fixed on GOG.

Well, Galaxy isn't required for playing the game: you might use it for downloading and installing the game (as a matter of fact, it can even download the backup installer files), then exiting it and run the game using its own executable outside Galaxy, hence not having it running in backgrounds.

I'm not having this problem: I've just checked starting the download on my browser and these files appear as 4GB of data as they should be, even though I haven't completed the download and haven't checked their integrity.

It seems that this is happening for quite a few different game downloads but is being investigated by support so hopefully it'll be sorted soon.
https://www.gog.com/forum/general/trouble_downloading_fallout_3_goty/post29