Make sure the username contains only English letters (no special characters, symbols, or non-Latin alphabet characters).

This method addresses the direct cause of the block without weakening your overall system antivirus defenses.

Right-click prototype2.exe and select Set affinity .

By applying the exclusive fixes above—specifically the or the Legacy IO registry tweak —you attack the root cause. You realign the game's perception of your Windows user account and force the save routine to use stable, legacy paths.

Open File Explorer and navigate to C:\Users\[YourUsername]\Documents\ .

Running the executable purely through the Steam client shortcut often fails to pass the necessary administrative tokens required to create new directory folders on modern platforms. Open your .

: Re-installing the game outside of the Program Files (x86) folder (e.g., directly to C:\Games ) can bypass system-level folder restrictions. 3. CPU Core Limitation (Affinity Fix)

The most common cause is the game's inability to write files to your "Documents" folder.