If asked to overwrite something, say “yes to all.” When installing updates to mods (or multi-part mods) and NMM asks if you would like upgrade to the new mod, select “no” and then select “yes to all” to have the update overwrite the original mod files, if there are any conflicting files.
Install Nexus Mod Manager and direct it to your Fallout NV folder if it does not detect it automatically.Follow these instructions and Fallout NV should work (mostly) fine: Fallout NV isn’t the easiest game to mod, but we have troubleshot and done our best to provide a bug-free mod list.
