Intel HD Graphics 620 (Dell)
4096MB ATI Radeon R7 M445 (Dell)
I was using this device:
to connect a Acer P191W monitor (which had no HDMI connector).
I performed a system reset while connected to the monitor.
After the reset, the laptop no longer displays through its own monitor unless the Intel Display driver is disabled in the 'Device Manager'.
If the Intel Driver is disabled, it works fine.
When the Intel driver is enabled, only the external monitor displays.
Dell want nearly £800 to fix it as it's now out of warranty. The laptop was £799 new. It's not worth dealing with Dell because of this reason.
But, would that not be an issue between you, dell, and Microsoft?
Also, the use of adapters is not supported. And, dell has a support community that may be able to help.