Read this, If you are crashing upon beginning Combat.

Aerid Thongar

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People are still posting this in the Bugs Section, so I thought I'd quickly solve the problem.  Firstly, if you are crashing after stating up the mod and entering a combat, the first thing to do is remember whether you have any mods installed in your copy of Native.  This mod, when it installs, sources files from Native to the mod itself, meaning any changes made, or additional data, is carried over.  So when the mod loads up, its trying to load altered data from your copy of Native, that it doesn't recognise. DON'T Immediately run to the bug forum when this happens. Run here.
Now, if you don't already do this, start keeping a "clean" copy of native, and keep backups of all your mods, so that there is no need to download them twice.  Its good to leave them in the rar or zip folders as backups, saves on memory space.  Hopefully you still have the 1866 folder and a clean copy of Native. However, the second thing you need to do, is remove 1866 completely. Its corrupt, and useless to you. The download however, if you still have it is fine, and ready to reinstall. Do not reinstall yet.
Nextly, remove Mount and Blade. at this point you may be screaming at me, DO WHAT? but just uninstall mount and blade.  Do you have backups of any mods installed in Mount and Blade? good. You need to have a clean copy of native to install 1866. So uninstall M and B, check the native folder does not exist, and then reinstall it, and update it, if you need to.  the next thing to do is reinstall 1866 to your mods folder. And to put your native back after removing all the mods you had in it, you can now reinstall them as you wish. Follow the instructions in this order, and you shouldn't have any difficulties. IF you have a pirate copy of M and B, then you really really suck, and i hope it doesn't work correctly for you.  :smile: other than that, happy shooting cowboys and girls!