Hello Alaskan,
Are you logged into the administrator account that installed Windows Defender?
Can you go to Windows Update, do an Express scan, and apply all offered
updªtes
http://update.microsoft.com
Are you on a large, managed network, where access to AutoUpdate is
restricted?
Is there a WSUS server on the network?
What version of WD are you now showing? Mine indicates
Windows Defender Version: 1.1.1593.0
Engine Version: 1.1.1904.0
Definition Version: 1.14.1941.7
Does that check out with you?