This is often a longstanding issue that either causes that: This refers to when the Window’sWindow’s File Explorer window is meant to crop up.

Posing for help with illegally downloading that data will end in an immediate ban or warning. Dumping your game data is that the only method that Cemu provides support for. Illicitly obtained game data also will cause this to happen. Try dumping the info from your Wii U again – reinstalling any game data won’t affect your saves. Sometimes Dumping software doesn’t work the way it’s intended to, but it’s better than not having it available.

To continue off of Cause #3, this might be caused by an incomplete or otherwise corrupt dump of your Base Game / Update / DLC copy.