There are reports of several new Metal Gear Solid V: The Phantom Pain bugs with the ability to render your save file unplayable. The first one is present on all platforms and can be triggered by Mother Base construction. Check out the full details below.
The second one affects only PlayStation 4 users, and occurs when multiple SEN accounts are used on the same console.
Thirdly, there’s a bug that occurs when you defend your FOB during Mission 43, that corrupts your save after the FOB mission is over. This happens on all platforms.
Be aware of these bugs when playing the game!
Source: Metal Gear Solid V Official Website, JunkerHQ