The error message "IOS_FS: Failed to write new FST" in Dolphin Emulator typically indicates that
Backward compatibility & safety
Minimal reproduction steps to include in issue report dolphin iosfs failed to write new fst
This error message is essentially Dolphin’s way of saying it can't save changes to its own internal "map" of the virtual Wii file system . In technical terms, refers to the File System module of the Wii’s operating system (IOS), and an FST (File Selection Table) is the directory structure that tells the system where every file is located. The error message "IOS_FS: Failed to write new
: On Android 11 and later, scoped storage restrictions can prevent the app from writing to certain directories, especially if games are stored on an SD card. Recommended Solutions Run as Administrator Right-click the Dolphin executable and select Run as administrator . This often bypasses basic permission blocks on Windows. Add Antivirus Exclusions Go to your antivirus settings (e.g., Windows Security Virus & threat protection settings ) and add the Dolphin installation folder and the Documents/Dolphin Emulator folder to the Exclusions Check Folder Permissions Right-click your Dolphin Emulator folder (usually in Documents). Properties and ensure the box is unchecked. tab, ensure your user account has Full control Relocate or Reset User Data (Advanced) Wii NAND Fix Confirm the target directory or device is writable