WSUS MMC Crashes and WSUS Generally unreliable.
Application Pool “WSUSPool” Stopped in IIS
To improve WSUS availability, you need to increase IIS Private Memory Limit. The default limit is set to 1843200KB. And when an IIS worker process uses more than 2GB WSUS crashes and the problem occurs.
Change Private Memory Limit (KB) to a higher number that fits your server specifications or simply 0 , which means no limit, instead of the hard-coded 1843200. Follow this path to find the setting:
WSUS Application Pool IIS Advanced Settings
Internet Information Services (IIS) Manager → Server → Application Pools → Select “WSUSPool” → Actions Advanced → Recycling → change “Private Memory Limit (KB)“.
This’ll improve WSUS availability.