[Open] Unable to open file

[Shadow99]

You are missing the file core_shaders.brf in your CommonRes folder
to fix it, you have to do the following steps:

1. Open Steam
2. Go to your Library
3. Hit right mouse button on your Mount and Blade game
4. Properties
5. Local Files
6. Verify integrity of game files

once its finished, you will be able to launch Warband again