Instead of downloading "fixed" files from untrusted sources, use these tools to repair or update your legally dumped copy:
: Use a tool like NSC_Builder or DBI to check the integrity of your .nsp or .xci file. This will tell you if the file is corrupted. celeste+switch+rom+fixed
To help you get the game running correctly, could you tell me: Are you trying to play on an emulator (PC) modded Switch specific error Instead of downloading "fixed" files from untrusted sources,