Windows 10: WiFi Download Speeds Stall

There is an issue with Receive Segment Coalescing (RSC) on Windows 10 that causes download speeds to stall while connected via WiFi.

Steps to disable Rsc using Microsoft’s automated tool:

1) Download the “.diagcab” file located here: https://aka.ms/diag_cssemerg11005 (UPDATE 2021-03-17: Link is dead)

2) Run it, and let it see if it can determine the problem and fix it.

3) Re-test your wireless internet connection.

Once the above is done the problem goes away.

• HT: Microsoft Answers: WiFi Issues with Creators Update
  • Via a client of ours

UPDATE 2021-03-17: Manual Instructions

The following requires an elevated PowerShell session. Click Start and type PowerShell then right click and Run As Administrator.

Steps to disable Rsc manually:

1. 1. Get your network adapter name:
      PowerShell: Get-NetAdapter
   2. Note your adapter’s name (Could be: Wi-Fi)
   3. Get your network adapter “Receive segment coalescing” (Rsc) settings:
      PowerShell: Get-NetAdapterRsc
      IPv4Enabled/IPv6Enabled: True
   4. Disable Rsc for your network adapter:
      PowerShell: Disable-NetAdapterRsc -Name NICName
   5. Verify Rsc is disabled for ipv4 and ipv6, on your network adapter:
      PowerShell: Get-NetAdapterRsc
      IPv4Enabled/IPv6Enabled: False

      7) Re-test your wireless internet connection.

Philip Elder
Microsoft High Availability MVP
MPECS Inc.
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