Never download an .exe file claiming to be a save. Only download save_data files (no extension) or .zip archives containing that file. Scan everything with VirusTotal.
Because Yuzu writes saves in real time (unlike a real Switch’s more atomic saves), crashing during a Spirit Battle or while loading a massive stage mod can corrupt your system_data . The symptom? Your control stick stops working in menus, or your name reverts to "Player 1". save data super smash bros ultimate yuzu