Symptoms

If you try to update SSM agent on an older instance with AWSConfig installed, SSM Agent will refuse to update, reporting issues caused by AWSConfig

Remediation steps

Backup your AWSConfig customisation

On Windows, config file can be found in C:\Program Files\Amazon\EC2Config\settings\config.xml Technically the installer WILL do the backup. But I prefer doing my own backups :)

Download the installer

If you are updating AWSConfig from version 3.x to 4.x you are probably ok, but if you are updating from 2.2.12 or earlier, please refer to the AWS documentation as there are issues with backwards compatibility which you have to go around by updating .NET and two stage installation

https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/UsingConfig_Install.html

Download and unzip https://s3.amazonaws.com/ec2-downloads-windows/EC2Config/EC2Install.zip

Install AWSConfig through PowerShell

EC2Install.exe /norestart

revert back the config.xml from backup

restart EC2Config service through msconfig.msc

Check the logs in C:\Program Files\Amazon\EC2Config\logs\

If you see WMI error, that might not be a big problem (I’ve seen it all over the place), but important part is the report of pushing out reports.

Install the latest SSM agent

https://docs.aws.amazon.com/systems-manager/latest/userguide/sysman-install-ssm-win.html