Quick answer: Write saves atomically, checksum them to detect corruption, and keep a previous good version so a corrupt save can be detected and rolled back.
A corrupt save with no backup is lost progress. Atomic writes and a fallback prevent it. Here is how.
How to fix it
1. Write atomically
Write to a temp file and swap it in so an interrupted write never corrupts the live save.
2. Checksum to detect corruption
Store a checksum so you can verify a save is intact before loading it.
3. Keep a previous version
Retain the last good save so a detected corruption rolls back instead of losing everything.
Catching the ones you can't reproduce
The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.
Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.
This is where a tool like Bugnet earns its place. Its SDK captures every backend error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.
Ship the fix, watch the signature disappear from the next build. That's how you know it's really gone.