Hi, it seems I need some help with installing the DLCs.

what I did:
1: downloaded the 15 part installer + 2 DLC installers (I used the manual files, not gog galaxy if that matters)
2: installed the game, which works
3: ran the DLC installer, which were successfully processed

The problem is that the DLCs are not visible in my game after this. In the main menu screen these show up as "now available".
I did reinstall once with redownloading everything, and it didn't work.

Anyone has an idea what I did wrong?
Thanks!

In the meantime, I uninstalled everything, got Galaxy, and tried installing through that.

The configure game menu has the DLC boxes marked, theoretically these are installed. Unfortunately Eridanos is still locked in my game (I am at Byzantium, completed Monarch, so both should be available).

I'm out of ideas.

SOLUTION
I had to install the game into C:\GOG\ instead of a custom folder. (originally it was in D:\user\my name\games\)
When I installed into C/GOG, the DLCs showed up.

Might be useful for others encountering this error.
Thanks a lot for the superb gog support for this tip!

So it has to be in C. Another reason not to buy it on gog. If they fix that then i consider to buy it here.
Installing in c is a no go for me. It's 2022 and the standard is that you're able to choose your own detination. I install every game into E,

It worked for me on drive D. No idea why it didn't for the other guy.