After buying Warband and the NW DLC I installed both and began playing NW online without issue. This week a few people I work with bought the games as well and we decided to try some after hours NW multiplayer at work but this time when I entered my serial number the game (NW) told meit was incorrect.

Since the game does not support pasting it's entireley possile I typed it wrong but at the very least I should get the option to re-enter it, which I don't. I have found some answers about how to solve this problem in Windows but I'm running it on Mac and so far I havn't been able to figure out where/how to change this number.

Note: I have tried re-installing the DLC (which is what I had entered the serial for) but this did not help. I have also seen people complain that re-installing the whole game did not help with this problem.

So it looks like when Steam first released this game on Mac people had a similar problem but steam took care of it. Is it possible that this is the same issue I am having... GOG?

Is this happening to anyone else?

also, *bump*

Best to contact support - http://www.gog.com/support/contact

On windows the key is saved in the registry, while on Mac and Linux it's supposed to be stored in a text file.
I'm not sure if GOG's Mac version uses the usual Linux version's file names and folders (can't check it here right now), but look for this hidden folder
~/.mbwarband/
and the files
serial_key and serial_key_nw

Delete the whole folder before re-installing or edit the files with any text editor.

I had contacted support around the same time I posted here but so far have not received a reply. I have also tried Taleworlds support (although I'm not sure if they can help me with GOG file structures) and haven't heard from them either. I haven't been able to locate these files but thanks for the suggestion. I'll keep trying!

*Bump*

Still haven't heard back from GOG support or Taleworlds support about this. Feeling desperate for a solution!

I would also bump your GOG ticket at least. The folder is more likely to be under your user's library folder than loose in your actual home folder. Is the Mac version native?

I've hunted all over the computer - the library in particular - but haven't seen anything related to M&B outside of it's app package.

Its the Napoleonic module that I'm having trouble with, not Native, although I haven't discovered where the serial for that gets stored either.

SOLVED

Well, no thanks to GOG or TaleWorlds I have finally solved this. Actually a while back but I forgot to post here.

So if you are running this game on Mac and need to change/correct your serial key, here is what you do:

1) Click on the 'Go" tab in your menu bar.
2) Hold the 'option' key and a hidden library folder will pop up. Select this.
3) In this library select 'Application Support"
4) Go down to the MBWarband folder
5) Open the serial_key document and change the key
6) Save and your done!

Hopefully this helps someone although it feels like I am the only one to have had this problem.