Windows Update service is disabled in OnApp Windows templates by default. It can be enabled using a few simple steps:
1. Open services.msc console, double-click on the Windows Update service
2. Choose "Automatic (Delayed Start)" in the "Startup type" field, apply the changes
3. Push the "Start" button and then "OK"
Also, you can enable and start the service with the following commands:
sc config wuauserv start= delayed-auto
net start wuauserv
If you want to do it automatically after the VM is built, just create a recipe with the mentioned commands: