No display on laptop's external monitor-Monitor recognized but blank

After the recent Windows 10 update, my wife's laptop no longer displays on the external monitor. All was well before the update.

I am comfortable that Windows sees the monitor because clicking on Display Settings shows two displays. If I unplug the HDMI cable, only one display is shown.

I have confirmed that the monitor works by trying it with another laptop. I have also changed the HDMI cable between the laptop and the external monitor.

Device manager reports that I have the latest display driver installed.

I would appreciate any and all suggestions.

Ken,
Yes, it is set to Extend. When I change it back to "PC Screen Only" the external screen goes black. When it is set to extend, there is a faint bluish glow on the screen.
Dave

In my 1607 Home, I have four options: Duplicate, Extend, Show only on 1, Show only on 2. Is "PC Screen Only" the latest way of saying one of the above?

May I assume the visible mouse cursor does not show up on the other screen in the extended mode? (the virtual orientation of the second screen relative to the primary screen may be different from the physical orientation. And the Update may have altered the accustomed condition? Just eliminating possibilities.)

May I assume the second screen is blank in the duplicate mode?

May I assume, if there is the option to show the desktop on the second screen only, that both screens go blank?

pyramid10

Each of your assumptions is correct.

When I set the display option to PC Screen only, the external monitor indicates that it is receiving no signal.
When it is set to Extend or Duplicate, the monitor indicates that it is receiving a signal and the screen has a very slight blue tinge.

Catalyst of for AMD video products. The laptop uses an Intel graphics chip. I've tried to update the drivers (installed are best) and tried the Intel graphic app, all to no avail.

Go to the Laptop manufacturers website and download the Intel HD Graphics driver. Install that then go to Windows updates.
What you want is a working driver not the latest.

My Laptop has Intel HD4600 Graphics and I have never messed with the driver it has always come from MS updates for 4 years. The external monitor has worked all the time thru Windows 8.1 thru all the version updates of Windows 10. Zero effort, it just works.

I presume you know where the Intel HD Graphics Control Panel is, Right Click desktop > Graphics Properties...
There are more options in there than the Windows 10 way.

Check the Laptop HDMI socket carefully for damage.