By default, the game saves to C:\Users\[Name]\Documents\My Games\Metal Gear Solid V - The Phantom Pain. This defeats the purpose of a portable drive.

The Fix: Symbolic Link Trick (Windows 11 Pro/Enterprise)

You cannot change the save path via .ini files. Instead, use a persistent symbolic link that works on any Windows 11 PC:

Better solution: Use a batch script (save_fix.bat) on the portable drive:

@echo off
set DRIVE=%~d0
mklink /J "%USERPROFILE%\Documents\My Games\Metal Gear Solid V - The Phantom Pain" "%DRIVE%\MGSV_Saves"
echo Save directory linked.

Run this as admin on any Windows 11 machine before launching the game.

Do not attempt any fixes without these:

Once the game launches, you need stability.

Executive Summary: Running a "portable" version of MGSV on Windows 11 typically results in three specific failures: the Safe Mode loop (stuck at 720p/low settings), missing save data (the game refuses to see your existing progress), and micro-stuttering due to Windows 11’s fullscreen optimizations. This guide addresses the architecture of the game engine (Fox Engine) and how it interacts with the modern Windows 11 environment.

After testing on three different Windows 11 machines (Desktop, Surface Pro, Steam Deck running Win11), here is the fix list: