What causes garbage from WaitForSeconds in coroutines?

Yielding new WaitForSeconds every loop iteration allocates a new object each time, so a coroutine that waits repeatedly generates steady garbage that feeds the collector.

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 Garbage from WaitForSeconds in Unity Coroutines

Quick answer: Cache the WaitForSeconds object and reuse it, or use a single cached instance for fixed wait times, to avoid per-iteration allocation.

WaitForSeconds garbage is allocating a new one each loop. Caching it fixes it. Here is how.

How to fix it

1. Cache the WaitForSeconds

Create the WaitForSeconds once outside the loop and yield the cached instance each iteration. Yielding new WaitForSeconds every time allocates an object per wait, generating continuous garbage.

2. Reuse for fixed waits

For a constant wait duration, a single cached WaitForSeconds works for all iterations. Only the duration matters, and it does not change, so one instance serves the whole coroutine.

3. Consider alternatives for variable waits

If the wait time varies, caching one instance does not fit. Use a manual timer accumulating deltaTime, or other non-allocating patterns, so variable waits also avoid per-frame or per-iteration allocation.

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.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.