If you use tools like Horizon or Modio to transfer Xbox 360 saves to a PC for editing, your console game version must match the version expected by the software.
Navigate to the following path on your main Xbox 360 Hard Drive: Hdd1:\Content\0000000000000000\5841128F\000B0000\ Terraria Xbox 360 Title Update Download
Terraria has different regional releases (US, EU, JP). You must find the Title Update that matches your exact disc region. Terraria's primary Xbox 360 Title ID is 5841128F . If you use tools like Horizon or Modio