Fix event 5117 – A worker process serving application pool ‘WSUSPool’ has requested a recycle because it reached its private bytes memory limit

On a Windows Server 2016 server with the WSUS role installed, you may encounter the following error

Log Name: System
Source: WAS
Event ID: 5117
Description: A worker process serving application pool ‘WSUSPool’ has requested a recycle because it reached its private bytes memory limit

In the WSUS Administration Console, you may face this message:

Error: Connection Error. Click Reset Server Node to try to connect to the server again.”

There are multiple ways to solve this issue. You most likely would want to use a cleanup script for WSUS. But that will cost some time finding and implementing the right one.

The quickest way to (temporarily? 🙂 ) fix this issue is to increase the memory assigned to the WSUS pool in IIS.

1. Open Internet Information Services Manager (IIS)
2. Go to Application Pools. Right-click WsusPool, choose Advanced Settings.
3. Scroll down to Private Memory Limit (KB) and set it to a much higher limit. Like 8000000 (8GB). This will most likely prevent the pool from running out of memory
   

Other events that may show up in your event viewer:

Event ID 5013
A process serving application pool ‘WsusPool’ exceeded time limits during shut down. The process id was ‘3000’

Event ID 5002
Application Pool ‘WsusPool’ is being automatically disabled due to a series of failures in the process(es) serving that application pool.