Dolphin does not natively support WBFS. Convert WBFS → ISO using Wii Backup Manager, then load ISO in Dolphin.
If you are downloading files from a Wii WBFS ROM archive or creating your own backups from physical discs, you will need specialized software utilities to manage, split, or convert the files. 1. Wii Backup Manager (Windows) Wii Wbfs Rom Archive
In the root of your USB drive or SD card, create a folder named exactly wbfs . Dolphin does not natively support WBFS
To manage these archives or convert files between formats, several utility programs are industry standards: Convert .iso Files to .wbfs (For USB Loader GX) Wii Wbfs Rom Archive