Maintain one dedicated folder for your base games, a separate temporary folder for installing updates/DLC, and a separate folder for Cemu itself. Never mix them together.
: If the meta folder is missing entirely, Cemu will not display the game in your library. This often happens with incomplete downloads or dumps. Re-downloading or re-dumping the game is often necessary. unable to find metaxml cemu new
Never store your base games inside the mlc01 folder. Keep base games in a completely separate folder on your drive. Maintain one dedicated folder for your base games,
One of the most common reasons people get this error is because they are trying to using the Update/DLC installer. Base games (which you typically source from dumping your Wii U disc or using a backup tool like Wii U USB Helper) are not meant to be installed this way. This often happens with incomplete downloads or dumps