Photon Fusion 2.x - Troubleshooting & Errors

This page is intentionally short, practical, and organized by symptoms.

Symptom: “Failed to spawn: behaviour not weaved”

Common error:

• NetworkObjectSpawnException: Failed to spawn: behaviour not weaved

Causes:

• the assembly containing your NetworkBehaviour is not in Fusion CodeGen “Assemblies to Process”

• CodeGen not run after changing asmdefs / define constraints

Fix:

• Tools → Fusion → Network Project Config → add the assembly

• Fusion → CodeGen → Run CodeGen

Symptom: Spawner works on host, clients see nothing

Causes:

• objects being spawned are not networked prefabs

• prefabs missing NetworkObject

• prefabs not registered in Fusion’s prefab list/table

• spawner running on the wrong peer (not authority)

Fix:

• ensure your spawned prefabs are network prefabs

• verify the spawner start call is only executed by the authoritative peer

Symptom: triggers don’t fire in Fusion (waves/regions)

Causes:

• trigger components still running in UnityPhysics mode on all peers

• driver missing / target not assigned

• collider/rigidbody rules not satisfied → no trigger callbacks

• activation layer/tag filters reject the collider

Fix:

• set WaveTrigger/LocalAreaSpawner to External mode

• add FusionWaveTriggerDriver / FusionLocalAreaSpawnerDriver

• verify tag/layers

• verify collider + Rigidbody setup

Symptom: wave activates multiple times

Causes:

• duplicate authority sources (two drivers, or UnityPhysics + External both active)

• overlapping triggers / multiple colliders

Fix:

• ensure only one system drives activation (External + driver)

• check for multiple driver instances

Symptom: pooling behavior differs from expectations

Notes:

• Runtime Spawner can run fine without replacing Fusion’s object provider

• If you want consistent pooling across spawner-spawned objects and your other networked objects, use one of the spawner’s Fusion pool providers (optional/recommended)