What causes a puzzle shuffle not guaranteeing a solvable result?

The shuffle randomly permutes pieces independent of the puzzle's reachability rules, so it can land on a configuration that no sequence of legal moves can solve.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a Puzzle Shuffle Not Guaranteeing a Solvable Result

Quick answer: Shuffle by applying random legal moves starting from a solved state instead of randomly permuting pieces, so every shuffled state is reachable and therefore solvable.

A shuffle button must always produce a solvable board. Random permutation ignores which states are actually reachable. Scramble by applying legal moves from the solved state, which keeps the result solvable by construction.

How to fix it

1. Scramble from the solved state

Begin with the puzzle solved and apply a long sequence of random legal moves. Because every move is reversible, the result is always solvable.

2. Avoid trivial or solved outcomes

Ensure the scramble does not accidentally end on the solved state or one move away; apply enough moves and re-scramble if the result is too easy.

3. Validate when permutation is required

If you must shuffle by permutation for performance, run the puzzle's solvability check (e.g. parity) afterward and reshuffle on failure.

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 GameMaker 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.