if Dolphin itself is running under standard user access.
The user directory (often in Documents/Dolphin Emulator ) or the installation folder might be set to "Read-Only".
Installing Dolphin into protected system folders like C:\Program Files often causes permission conflicts. How to Fix "IOS_FS: Failed to Write New FST" 1. Adjust Windows Security & Antivirus dolphin iosfs failed to write new fst
Since background processes are a major suspect, you should configure your security and productivity software to ignore Dolphin's activities.
Add the folder where Dolphin.exe is located, as well as the user data folder (usually in Documents\Dolphin Emulator or %AppData%\Dolphin Emulator ). 2. Run as Administrator if Dolphin itself is running under standard user access
Minimal reproduction steps to include in issue report
Alternatively, create a blank file named portable.txt in your main Dolphin installation folder. This forces Dolphin to save all settings and FST data locally in that folder instead of "Documents" . 3. Administrative Privileges How to Fix "IOS_FS: Failed to Write New FST" 1
What are you running (Windows 10/11, macOS, Linux)?
Add the entire folder containing your Dolphin application executable, alongside your global user folder (typically found at C:\Users\[Username]\Documents\Dolphin Emulator ), to the exclusion list. 3. Review Folder Permissions and "Read-Only" Status