Quick answer: Issue a guest identity at first launch, let players link a real account later that adopts the guest's progress, and warn before any action that would lose unlinked progress.
Guests who lose progress on reinstall rarely come back. Account linking saves them. Here is how.
How to fix it
1. Issue a guest identity
Create a backend-backed guest account at first launch so progress is server-side from the start.
2. Link to a real account
Let the player attach an email or platform account that takes over the guest's progress.
3. Warn before loss
Prompt players to link before doing anything that would strand unlinked progress.
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.
The bug you can't reproduce isn't gone — it's just invisible until you capture it from the player's device.