Add the Dolphin installation folder and the user data folder (usually Documents\Dolphin Emulator ) to the exclusion list.
Instead of relying on Dolphin’s built-in write, use from command line: dolphin iosfs failed to write new fst
: The directory where Dolphin is installed or where it stores user data (often Documents/Dolphin Emulator ) may be set to Antivirus Interference : Security programs like Windows Defender Add the Dolphin installation folder and the user
Additional notes
If your game is in .gcz or .wbfs format, you cannot write a new FST directly. dolphin iosfs failed to write new fst