How to Fix a Tech Tree Unlocking Units Before Prerequisites Exist in Unity

If a player can pump out tier-3 units with only a town hall, your tech gating is decorative. Production must check live prerequisites. Here is how to enforce the tree.

How to fix it

1. Define prerequisites as data

Give each buildable a list of required building types and required upgrade IDs. Keep this in a ScriptableObject so designers can edit the tree without code.

2. Evaluate against live ownership

Before enabling a build option, confirm the player owns at least one of each prerequisite building and has every required upgrade completed. Disable and grey out anything not yet met.

3. Re-check at command time

Validate prerequisites again when the build command executes, not just when the button renders, so losing a tech building mid-queue cannot let an invalid unit slip through.

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.