can someone please tell me why the material preview is not updading?

very new to 3ds Max so sorry for silly question.

I guess I have pressed a button, the preview on materials are all black?

auto update is switched ON

Try this
https://coronarenderer.freshdesk.com/support/solutions/articles/5000568654-1-0-issues-sample-slots-in-material-editor-not-displayed-properly

fixed! thanks!