This happens if you are using an XCI file that is corrupted or poorly dumped. Re-dump the game using NXDumpTool or acquire a clean NSP version of the base game. Game Asks for a System Update
Check your game version on the Switch home screen by pressing the (+) button. Ensure you have downloaded and applied the most recent NSP update, as older versions of the game cannot read newer DLC data. "Corrupt Data Detected" kao the kangaroo rom nsp update dlc switch work
Delete the game completely from your Data Management menu. Re-download a matching Title ID set for the base game and update, then reinstall them cleanly. To help narrow down any performance bugs, tell me: What Custom Firmware version (Atmosphere) are you running? This happens if you are using an XCI
This means your system detects a mismatch between the base game version and your system's cached update data. Install the latest available NSP update file. Ensure you have downloaded and applied the most
The most common reason Kao the Kangaroo updates or DLC fail to load is outdated signature patches (sigpatches) or system firmware.