Traffic Drops After Windows Update

There is currently a Windows Security Update that can cause NDI traffic to drop unexpectedly on computers with this update installed.

The affected updates are:

Windows 11 – KB5063878 https://support.microsoft.com/en-au/topic/august-12-2025-kb5063878-os-build-26100-4946-e4b87262-75c8-4fef-9df7-4a18099ee294

Windows 10 – KB5063709 https://support.microsoft.com/en-au/topic/august-12-2025-kb5063709-os-builds-19044-6216-and-19045-6216-96d99cf6-f8b5-4798-9892-4e3eb8f11548

Symptoms

When this update is installed, NDI connections may drop unexpectedly during use. The problem occurs only with RUDP connections, while traffic sent or received using UDP or Single-TCP remains unaffected.

Check if you have the affected update installed

1. Open Settings in Windows.

2. Select Windows Update.

3. Select Update History.

4. Select Uninstall Updates.

5. Look for Security Update for Microsoft Windows (KB5063878 or KB5063709).

If you don’t have it installed, we recommend delaying installation until a fix is released. However, depending on your update settings, it may install automatically in the future.

How to solve

Option 1 (recommended): Manually change the NDI Receive Mode to use TCP or UDP instead of RUDP.

1. Download and install the free NDI Tools pack.

2. Launch the NDI Access Manager app.

3. Go to the Advanced tab.

4. Change Receive Mode to Single TCP or UDP, then press OK.

5. Repeat on any other affected computers.

Option 2: Uninstall the Windows Security Update.

1. Open Settings in Windows.

2. Select Windows Update.

3. Select Update History.

4. Select Uninstall Updates.

5. Find Security Update for Microsoft Windows (KB5063878 or KB5063709) and click Uninstall.

Windows may reinstall the update at a later date, so Option 1 is generally preferred unless you rely on workflows that specifically require RUDP.