How do I prevent crashes caused by bad save data?

Load defensively, version your format, and watch the field. Validate save data on load, check it's well-formed before using it, and handle corruption gracefully by falling back, repairing, or warning rather than crashing, since a save that crashes on load will crash every time until handled, locking the player out. Version your save format and write migrations so saves from older builds are upgraded rather than breaking when an update changes the format, this protects your most invested players when they update. And capture load crashes from the field with context, since you can't anticipate every way a save goes bad in the wild, so the patterns let you fix the handling. Bad-save crashes are especially damaging because they cost players their progress, so they're worth preventing deliberately.

Why does my game crash when loading certain saves?

Usually because the save is in a state the loading code doesn't expect, and the code assumes validity instead of checking. The common causes are corruption (the save file got truncated or damaged, e.g. from a crash or interrupted write during saving), a format mismatch (an update changed the save structure, so an old save no longer matches the new code's assumptions), or unexpected values the loader doesn't handle. Because loading code often assumes a complete, valid, current-format save, any deviation crashes it, and since the bad save doesn't change, it crashes every load attempt. Validating on load, handling corruption gracefully, and versioning the format with migrations prevent these, and capturing load crashes from the field reveals which is happening.

How do save format changes cause crashes after an update?

When an update changes how saves are structured, the new code reads old saves with new assumptions, and any mismatch crashes the load. For example, if a new version expects a field that old saves don't have, or interprets existing data differently, loading a pre-update save can fail and crash, every time, since the save is fixed. This hits your most invested players hardest, the ones with existing progress who update and suddenly can't load their game, which is both a stability problem and a serious trust problem. The prevention is versioning your save format and writing migrations that upgrade old saves to the new format on load, so progress carries forward instead of breaking. Per-version crash monitoring catches it fast if a format-change regression slips through, since save-load crashes spike right after the update.

How to Prevent Crashes From Bad Save Data

Quick answer: Validate save data on load and handle corruption gracefully, version your save format so old saves migrate, and capture load crashes from the field. Bad-save crashes can lock players out of their progress.

A crash caused by bad save data is especially painful, the player loses access to their progress, and may crash every time they try to load. Preventing it protects both stability and player trust. Here's how to prevent crashes from bad save data.

Validate Save Data on Load and Handle Corruption Gracefully

Crashes from bad save data happen when the game loads a save and assumes it's complete and valid when it's corrupted, truncated, or unexpected. So validate save data on load, check it's well-formed before using it, and handle corruption gracefully (fall back, repair, or warn) rather than crashing. Defensive loading prevents a bad save from taking down the game.

Bugnet captures crashes with breadcrumbs, so you can see when a crash happens during save loading. Validating and handling bad save data prevents the load crashes that otherwise lock players out, since a save that crashes on load crashes every time until handled.

Version Your Save Format So Old Saves Migrate

A common cause of save crashes is an update changing the save format so old saves no longer load, the game reads an old save with new assumptions and crashes. So version your save format and write migrations, so saves from previous versions are upgraded rather than breaking, preventing crashes for players who update with existing progress.

Bugnet tracks crashes per version, so a wave of save-load crashes right after an update points at a format-change regression. Versioning and migrating saves prevents the update-driven save crashes that punish your most invested players, the ones with existing progress, exactly who you least want to lose.

Capture Load Crashes From the Field

You can't anticipate every way a save goes bad in the wild, so capture load crashes from the field with context. When crashes cluster around save loading, you can see the pattern and fix the handling, preventing the bad-save crash from continuing to lock out players who hit it.

Bugnet captures crashes with context and per-version data, so save-load crash patterns are visible. So prevent crashes from bad save data by validating and handling corruption on load, versioning your save format with migrations, and capturing load crashes, protecting players' progress and your stability.

Validate save data on load and handle corruption gracefully, version your save format so old saves migrate, and capture load crashes from the field. Bad-save crashes cost players their progress, so prevent them deliberately.