---
title: "MFLink stays stuck on “Synchronization in progress” or “Boarding” with X-Plane"
description: "If MFLink never gets past \"Synchronization in progress\" or \"Boarding\" when you fly in X-Plane, the most likely cause is your XPUIPC version. ### Why it happens XPUIPC now exists as two separate products. The classic **XPUIPC** (version 2.0.x) works…"
url: "https://metaflight.aero/docs/mflink-stuck-synchronization-boarding-x-plane/"
updated: "2026-10-21"
category: TROUBLESHOOT
---

# MFLink stays stuck on “Synchronization in progress” or “Boarding” with X-Plane

If MFLink never gets past "Synchronization in progress" or "Boarding" when you fly in X-Plane, the most likely cause is your XPUIPC version.

### Why it happens

XPUIPC now exists as two separate products. The classic **XPUIPC** (version 2.0.x) works with MFLink. The newer **XPUIPC+** restarts its numbering at 0.x and is a different plugin: MFLink does not currently work with it. Because its version number looks lower, it is easy to install it by mistake.

### Step 1: Check which plugin you have

1. Open your X-Plane folder, then **Resources > plugins**.
2. If you see a folder named **XPUIPC+**, you have the new version.

### Step 2: Remove XPUIPC+

1. Close X-Plane and MFLink.
2. Delete the **XPUIPC+** folder from **Resources > plugins**.

### Step 3: Install XPUIPC 2.0.3.5

1. Download **XPUIPC 2.0.3.5 + XPWideClient 2.0.0.3** from the [XPUIPC repository](https://fsacars.com/downloads/xpuipc/) (third-party site). Take that exact entry, not the newer builds listed above it, then extract the archive.
2. Copy the **XPUIPC** folder directly into **Resources > plugins**. Make sure it is not nested inside another XPUIPC folder.

### Step 4: Check and fly

1. Start X-Plane and load your aircraft.
2. Open the **Plugins** menu: **XPUIPC** must be listed.
3. Start MFLink and launch your flight.

If MFLink is still stuck, follow [How can I fix synchronization issues between MFLink and FSUIPC/XPUIPC?](https://metaflight.aero/docs/how-can-i-fix-synchronization-issues-between-mflink-and-fsuipc-xpuipc-2/), then [open a support ticket](https://metaflight.aero/docs/how-do-i-open-a-support-ticket/).