I APOLOGIZE IF THIS IS THE WRONG PLACE FOR THIS!!
I apologize if this is a common issue and I'm an idiot.

Hello I'm a long time but infrequent user and just attempted to install the new FOLON mod/game :D
I never thought I'd be the one to have issues due to my deep understanding of Fallout and all it's quirks
but I don't know GOG well so here I am haha.

This error appears the second I launch the GALAXY installer or any game installers from my GOG library.
(I presume this is due to me not having the launcher installed so they all attempt to install it)
If I launch with admin rights nothing happens at all, no process in the TM related to GOG.

I have attempted a reboot and bios user swap as I have an admin and a user logon pre boot.
I am going to boot to my windows 11 install to reproduce these issues as my OS is not popular.

My Hardware
Device name DESKTOP-LN6GBG1
Processor AMD Ryzen 5 2600X Six-Core Processor 3.60 GHz
Installed RAM 32.0 GB
Device ID 41D00E1A-24C3-4F9A-B4F2-1E49F7BEF7D1
Product ID 00331-60000-00000-AA041
System type 64-bit operating system, x64-based processor
Pen and touch No pen or touch input is available for this display
GPU : RX 7600

Ext. My OS

Edition Windows 10 Pro N
Version 22H2
Installed on ‎2024-‎05-‎23
OS build 19045.4717
Experience Windows Feature Experience Pack 1000.19060.1000.0

I can send any information you require besides my SIN number.

I get the same exact problem.

My solution to this problem in the meantime is to just manual download all of the parts for both the game and the mod and try to put them together. I'm hoping there is some kind of a read me in the zip file after I combine them and extract.

That's what I had to do for cyberpunk when I purchased it from GOG earlier in the year.

It will probably end up a bit more complicated figuring out this mod. I'll let you know if it works, if I figure it out I will let you know what I did so that hopefully you can follow my footsteps and end up playing the game too.

For now I'm in the same boat that you are in. I've never been able to get GOG Galaxy to download or work. So everything I've bought on here I've had to manually download, which can be a nightmare with massive games like cyberpunk that thing has a ton of parts.

Exact same issue, same error message too. I thought it was an issue on my end and almost messed up my BIOS settings...