Installer runs fine, but at the end it asks me to select a folder for the mod. I presume it wants me to click on the M&B Warband app, but it's unelectable in finder. So what do I do to finish installation?

GOG Games\Mount and Blade - Warband\Modules have you tried selecting modules folder?
Also not a mac user i have windows so if this doesn't work maybe someone else will know.

I have the exact same problem. Purchased both games via GOG. Nap Wars installer prompts me to select a location, without really specifying what it wants, I've tried several different options here, but all that happens i an error: "Installation failed! Game bundle not found in selected location".

Suggestion anyone?

Select the location where you installed the original Warband (for me, was in my Applications folder). HOWEVER, i have this and the Viking module installed and can't seem to start either of these add-ons. I can only play the original version. All the files are there in the folder in Applications folder, but don't get the option to start either one...

So, i installed it, but still can't seem to play it... Not sure if anyone else is having that problem?

This may not be what you're looking for, but I installed this today on GoG galaxy and it just worked with this DLC on a Mac. The first menu comes up with I "play" it and I have to choose which mod to use.

Thanks!! I just did it thru GOG Galaxy and all mods and native Warband work now.

FWIW - I tried to play it by starting thru Applications folder and notice that it will launch the game but only the last Module I started via GOG Galaxy (e.g., if I played Viking while starting thru GOG, even when offline when i started it, launching thru the Application folder will ONLY play the Viking mod). Weird, but at least it works now!

Thanks again!!