Project-M/Docs/UnityBugReport-Netcode-Transport-6.6.0a6.md

🛑 DO NOT FILE — WITHDRAWN 2026-05-31. This was not an engine bug. A clean, fresh Unity 6000.6.0a6 project (../Local Reference, a full Netcode-for-Entities framework) runs netcode fine on the same alpha. The failure was specific to Project M's environment (in-place 6.4→6.6 upgrade + embedded Entities-1.x com.rukhanka.animation package + default driver/AutoConnect path). See Docs/Vault DR-002 → "Correction". Kept only as a record of the investigation.

Unity Bug Report — Netcode for Entities / Unity Transport (6000.6.0a6)

Copy-paste into the Unity Bug Reporter (Help ▸ Report a Bug) or the Unity Discussions/issue tracker. Captured 2026-05-30 from Project M. Background: DR-002_Unity66_Alpha_Netcode_Transport.

Title: [Netcode for Entities] In-editor client↔server connection never establishes — Unity Transport throws Trying to access an invalid wrapped network interface every frame (6000.6.0a6)

Package(s): Netcode for Entities com.unity.netcode 6.6.0 · Unity Transport com.unity.transport 6.6.0

Severity: Blocker — no Netcode-for-Entities connection can be established in the Editor; networked play is unusable.

Unity version: 6000.6.0a6

Re-resolved package versions on this editor:

• com.unity.netcode 6.6.0
• com.unity.transport 6.6.0
• com.unity.entities / com.unity.collections / com.unity.entities.graphics 6.5.0
• com.unity.physics 6.5.0
• com.unity.burst 1.8.29 · com.unity.mathematics 1.4.0

Environment: macOS (Apple Silicon), OSXEditor, URP 17.6. In-Editor (not batch mode).

---

Description

Any standard Netcode-for-Entities setup that creates a ServerWorld + ClientWorld and auto-connects (the default ClientServerBootstrap with AutoConnectPort set, RequestedPlayType = ClientAndServer) fails to ever establish a connection in the Editor. The client creates a NetworkStreamConnection entity, but the server never accepts it and no NetworkId is ever assigned to either side.

Every frame, the Console floods with:

Exception thrown in a managed function called from unmanaged code:
System.InvalidOperationException: Trying to access an invalid wrapped network interface.

When the Jobs Debugger is enabled, this is accompanied by a cascade of dependency-safety exceptions across Unity Transport's internal layered-driver jobs, e.g.:

InvalidOperationException: The previously scheduled job NetworkDriver:UpdateJob writes to the
Unity.Collections.NativeList`1[...]. You are trying to schedule a new job
SimpleConnectionLayer:ReceiveJob`1 / SequenceReorderingLayer:ReceiveJob / TopLayer:CompleteReceiveJob /
AnalyticsLayer:AnalyticsJob / BottomLayer:ClearJob / RpcSystem:RpcExecJob ...
To guarantee safety, you must include NetworkDriver:UpdateJob as a dependency of the newly scheduled job.

and subsequently:

[Netcode] Server Tick Batching has occurred due to the server falling behind its desired SimulationTickRate ...

Disabling the Jobs Debugger (JobsUtility.JobDebuggerEnabled = false) removes the dependency-safety exceptions, but the Trying to access an invalid wrapped network interface error persists and the connection still never forms — so the invalid network interface is the root cause, independent of the safety checks.

Steps to reproduce (minimal — no gameplay content required)

1. New project on 6000.6.0a6; add com.unity.netcode (6.6.0; Entities 6.5.0 / Transport 6.6.0 resolve automatically).
2. Add this bootstrap (the only script needed):

   using Unity.Entities;
   using Unity.NetCode;
   using UnityEngine.Scripting;
   
   [Preserve]
   public class TestBootstrap : ClientServerBootstrap
   {
       public override bool Initialize(string defaultWorldName)
       {
           AutoConnectPort = 7979;          // in-editor auto-connect (ClientAndServer, IPC)
           CreateDefaultClientServerWorlds();
           return true;
       }
   }
   

3. Open any scene — an empty scene (camera + light only; no SubScene, no ghosts, no systems) is sufficient.
4. Enter Play Mode.

Expected

The in-process client connects to the server over IPC; the server assigns a NetworkId; a NetworkStreamConnection is established on both worlds. No Transport exceptions.

Actual

No connection forms.

• ServerWorld: 0 NetworkStreamConnection, 0 NetworkId.
• ClientWorld: 1 NetworkStreamConnection, 0 NetworkId.
• Console floods every frame with Trying to access an invalid wrapped network interface (plus Transport job-safety exceptions when the Jobs Debugger is on).

Frequency

100% reproducible. Occurs with zero gameplay content (empty scene + the bootstrap above), confirming it is not project-specific.

Regression / likely cause

• Netcode for Entities + Unity Transport are transitioning to built-in Core packages (since 6000.5.0a7), which renumbered them into the 6.x editor line.
• The 6000.6.0a5 changelog states Netcode snapshots were reworked to use Unity Transport's "unreliable sequenced pipeline" — the same SequenceReorderingLayer / layered-driver path that throws here. The regression appears to coincide with that rework.

Known-good baseline

The same setup works on Unity 6.4.x (Netcode for Entities 1.13.2 / Unity Transport 2.7.2).