The file should be named exactly FIFA_Next_Season_Mega_Patch_Tashee_x00.part12.rar .

Updated promotion/relegation for the Premier League, La Liga, Bundesliga, and more. Step 1: Downloading Part 12

Ensure you are downloading from Tashee’s official channel or a verified modding forum (like EvoWeb or FIFA-Mods).

You must have every single part (Part 1, Part 2, etc.) in the same folder.

If WinRAR asks for "Volume 13," it means you are missing the next part in the sequence.

Because of the massive size of these patches (often 20GB+), creators split them into smaller parts (e.g., Part 1 through Part 15).