I stumbled across this error when attempting to perform a Pre-Update check on my vCenter server. “Update 18.104.22.16800 not found. Please provide a valid update version” and “Update 22.214.171.12400 not found. Please provide a valid update version” This is a potentially a bug with Release 126.96.36.19900 vCenter Build 16189094.
I decided to check the VAMI https://vCenter-URL:5480 and initiated the update to 188.8.131.5200. After the update completed, I was able to successfully perform the Pre-Update check for Release 184.108.40.20600.
I’ve confirmed this behaviour on two vCenter that are on Release 220.127.116.1100 vCenter Build 16189094, so my best guess is that this is a bug. I hope you found this useful. 🙂