Solved! Lenovo Yoga Black Screen after disconnecting from external monitor

[ckng9000]

Lenova Yoga 900 13-isk

Both Laptop screen and Monitor screen show the display but when disconnected from external monitor laptop screen becomes black.

Try to reboot from laptop disconnected to external monitor. It boots with windows welcome sound but the screen is black with function keys that don't work at all.

When plugged in to ext. monitor it shows the displays on both laptop and monitor.

Updated the graphic driver to 2016(Latest) still the same issue (Can only install lenovo manufacture drivers)
Uninstalled the graphic driver went back to Microsoft Generic Display and that works with no problem but cannot project to an another monitor or projector
Update: Upgraded the graphic driver to 2019 still the same issue.

 

[Prostar Computer]

Have you tried using the designated hotkeys to toggle displays? If the laptop doesn't have its own designated keys, you can use the Windows key and P key; a menu will show up on the right side where you can select your built-in monitor only.

And why can you only install the Intel driver from the Lenovo site?