My game progress is lost!

Konami has revealed a bug which kills your saved game.

This bug triggers when you bring Quiet with you on "Mission 29" or "Mission 42".

If you want to be 100% sure this does not happen to you, then you don't bring her as a buddy on the missions mentioned above.

UPDATE: Konami has revealed a work-around.

As previously communicated, a critical bug has been identified that may halt progress and corrupt game save data under certain circumstances. Further investigation has revealed the exact trigger of the bug, so we would like to share these details to enable players to effectively avoid the issue.

The bug is triggered only under certain circumstances in Episode 29 or Episode 42 when Quiet is used as your buddy. However, you may still safely use Quiet in these missions if you use the Butterfly Emblem throughout the mission or avoid raising your Bond Level with Quiet to MAX during the course of the mission.