SOLVED !!
I had update MDL from:
MDLMaterialExchange v18.0.7090
to:
mdl-material-exchange-nt-x86-64-19.2.1814-325000.1814
and vMaterialsd from vMaterials_v1.6.0 to vMaterials_v1.7.0
I went to this site:
and downgrade to
NVIDIA vMaterials v1.6.0
https://d3fcmia9cdl7u7.cloudfront.net/packages/vMaterials/vMaterials_v19.1.3521.exe
(VERY strange is that after install, Win 10 Control Panel says the version is vMaterials_v19.1.3521 !!)
and vMAterial to:
NVIDIA MDL Material Exchange v18.0.7090
Now 3D Max 2018.4 does not show the MDL errors anymore!
My NIVIDIA card is an old GeForce 820A.
Hope this helps others!!
LAO