What causes a resumed run desyncing its RNG after loading a save?

You save the run's data but not the RNG's internal state, so on resume the RNG restarts from its seed (or a fresh state) and future generation diverges from what would have happened.

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 Resumed Run Losing Its RNG State

Quick answer: Serialize the RNG's full internal state (or seed plus draw count) with the save and restore it on load so the random sequence continues exactly where it left off.

Resuming a run should be seamless, but if drops change after a reload, the RNG state was not saved. Persisting and restoring the full RNG state keeps the sequence continuous.

How to fix it

1. Serialize the RNG state

Save the RNG's internal state alongside the run. With a custom PRNG, store its state variables; with a counter-based RNG, store the seed plus the number of draws consumed.

2. Restore before generating

On load, reconstruct the RNG from the saved state before any generation runs so the next draw matches what the live run would have produced.

3. Use a resumable RNG design

Prefer a counter-based or explicit-state PRNG over an opaque global generator so the state is straightforward to serialize and restore deterministically.

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 Unity 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.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.