Z20t loses extended display

 Normally I have a two external monitors.
DEL connected by HDMI and LG connected HDMI to a USB-HDMI adapter. 

PROBLEM: If I unplug the external monitors and move my computer and connect the projector by HDMI, when I bring my laptop back to my desk, it does not connect to the DEL.  The LG via USB is fine.

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Friday 13-08-2021

Same problem.  Yesterday it was working fine.  Shut down when I left last night.  Powered up this morning (both monitors connected) but no pictures on either.  Unplugged.  Rebooted.  Plugged in the Dell (HDMI) - Nothing.  Plugged in the LG (voa USB) and t has come up.  So now I have the PC LCD display and the LG.  No Dell.

HD Graphic 5300
Driver Provider: Intel Corporation
Drover Date: 21-01-2020
Driver Version: 20.19.15.5126
Digital Signer: Microsoft Windows Hardware Compatibility Publisher.

UPDATE Driver-> Search aautomatically--> The best drivers are alreay installed
   -> Search for updated drivers on Windows Update.
This just takes one to the Update and Security>Windows Update screen.

TOSHIBA SUPPORT
Tochiba is now "Dyna book"
https://support.dynabook.com/support/modelHome?freeText=1200015982
They have Intel Display Driver which is older than what I have
     Posted Date: 2017-12-19 | Version: 20.19.15.4549
I note they do have some 2021 drivers-
Toshiba System Driver
    Posted Date: 2021-07-29 | Version: 1.01.0002 | Size: 18.63M

INTEL SUPPORT
https://www.intel.com.au/content/www/au/en/support/products/84188/graphics/graphics-for-5th-generation-intel-processors/intel-hd-graphics-5300.html

Drivers>

1. Unplug both monitors.
2. Power down
3. Power ON
4. Plug in Dell (HDMI) Nothing
5. Plug in LG via USB - OK.
6. Unplug BOth. 
7. Plug LG into HDMI - Nothing.
8. Plug LG back into USB - OK.

9. Install the new Graphics driver V15.40.48.5171
Fail - Not validated for this hardware.
My Processor is Intel(R) Core(TM) M-5Y71 CPU @ 1.20GHz   1.40 GHz
10 Create Restore Point
11. Install the new Toshiba system driver

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Monday, July 12, 2021

1. Reboot PC
Close all programs.
Unplug both monitors.
Reboot.

Plug the Dell back in on the HDMI. - > No go

2 Plug the LG into the HDMI
Unplugged the Del HDMI.
Removed the HDMI plug from the USB-HDMI adaptor.
Plugged into the HDMI on the laptop. --> Fail

This implies it's the laptop

3 Shut down
Tried a shut down then press the power button to start.
Neither display connected.
Booted & Waited.
Then plugged in the DEL via HDMI --> Worked

So I think this confirms the hardware is OK and that it is some kind of software or driver issue.

Display Adaptors
Driver Provider: Intel
Driver Date 21/01/2020
Driver Version 20.19.15.5126

Monitors
DELL U2412M(Digital)
Driver Provider:  Dell Inc
Driver Date 15/06/2012
Version: 1.0.0.0

c:\WINDOWS\System32\drivers\monitors.sys
File Version 10.0.19041.488 (WinBuild.160101.0800)

4Unplug Replug
So lets just try unplugging and re plugging.  Wait a minute between.
That works.

5 Now try putting the LG in place of the Del on HDMI
That worked.

6 Back to the Dell
Unplug the LG and thenplug in the DEL - Works.
So maybe the video projector is causing it.

By the time I did all of this the screens were messed up.
Rebooting fixed it

As a FYI,
My monitors are 213

Unplugged and did some stuff.
Now the LG does not connect.