Are you playing the game through or a different launcher? Do you use OneDrive to backup your Documents folder?
The most common culprit is Windows Defender's "Controlled Folder Access," which views Prototype 2 as a suspicious application trying to modify your personal files. prototype 2 failed to save data fix exclusive
: Right-click prototype2.exe and select Properties . Are you playing the game through or a different launcher
After applying any of the above (preferably #1 + #2 together): prototype 2 failed to save data fix exclusive