OH! I also tried many times to mess with the launch settings (before and after messing with the patch, by the way). For some reason, when I start that, it pulls up a DOSbox window, then it quickly expands to fullscreen and crashes out. Launch Settings won't really work for me at all unfortunately. If there was another way to start that that might actually work, I'd like to try it.
I decided to do a full install from scratch, and found out that for the install program to run you need a readme.txt file found in \Realms of the Haunting\DATA to be put in Realms of the Haunting\ROTH.
If you want to follow along with the install process, here's what I did:
Downloaded the current setup_realms_of_the_haunting_126.96.36.199.exe from my GOG library
Downloaded the patch from: https://community.pcgamingwiki.com/files/file/746-realms-of-the-haunting-uk-to-us-patch
Installed ROTH to my games\gog folder *Don't use program files as an install area
Installed the patch as so: https://www.gog.com/forum/realms_of_the_haunting/resolution_and_sound_after_us_patch/post1
*A simple extract to path doesn't do the trick, you need to extract multiple times the same file to different directories.
From the data in the zip to
\Realms of the Haunting\DATA\DATA
\Realms of the Haunting\ROTH\DATA
From the gdv in the zip to
\Realms of the Haunting\DATA\GDV
From the m in the zip to
\Realms of the Haunting\DATA\M
\Realms of the Haunting\ROTH\M
The rest of the files not in folders (.exe , .ini, .dat) to
\Realms of the Haunting\DATA
\Realms of the Haunting\ROTH
"Launch settings" seems to be missing, so we'll just temporarily edit the dosboxROTH_single.conf and add "install" to it:
It also needs the readme.txt to function, so copy \Realms of the Haunting\DATA\readme.txt to Realms of the Haunting\ROTH
Run "Launch Realms of the Haunting" and choose the correct audio settings. Return dosboxROTH_single.conf back to normal.
I also like to edit dosboxROTH.conf to make the following audio changes:
Run the game! The opening interplay video will likely be a bit messed up, but that shouldn't happen with any of the other videos. "c" and "v" will play with the gamma settings.
's' picks up items in your inventory. This is useful to change the order of what weapons are available in your # hotkeys, as well as to use potions (place potion on hand icon beside portrait).
Once you have it running properly you may want to consider changing output=opengl in dosboxROTH.conf, as that should give you smoother gameplay.
Or even updating DosBox to a more modern build like staging or ECE. (Being able to use opengl with glshader=sharp is a very nice visual combo!)