Microsoft is currently not providing updates to Windows 7/8.1 for users of the following CPU architectures: Intel seventh (7th)-generation processors (Kaby Lake), AMD "Bristol Ridge" (Zen/Ryzen), Qualcomm "8996" .
From MS Article ID: 4012982
This error occurs because new processor generations require the latest Windows version for support. For example, Windows 10 is the only Windows version that is supported on the following processor generations:
Intel seventh (7th)-generation processors
AMD “Bristol Ridge”
Because of how this support policy is implemented, Windows 8.1 and Windows 7 devices that have a seventh generation or a later generation processor may no longer be able to scan or download updates through Windows Update or Microsoft Update.
On a side note, it's surprising just what is powered by AMD's Ryzen CPU.
I guess Walter's OS isn't Windows 7!