Follow the guidelines below to resolve an issue with the Dell Thunderbolt Dock (TB16) External Display detection not retaining when the Switchable Graphics mode is disabled NVidia graphic configurations.
You may find that some monitors cannot be detected or initialized after unplugging and re-connecting the Dell Thunderbolt Dock (TB16) cable to your Precision 7710 or 7510 mobile workstation system.
This issue has been seen when you connect three (3) external displays to a TB16 using the DisplayPort (DP), High Definition Multi-Media Interface (HDMI) and mini DisplayPort (mDP) connections on a Precision 7710 or 7510 mobile workstation system that has the switchable graphics option disabled in the Basic Input/Output System (BIOS).
Disconnecting then re-connecting the Dock Thunderbolt cable connection to the system may restore detection of these displays.
Installation of the new NVidia graphics driver, Version 21.21.13.6972, A03 or latest available, downloaded from the Dell Support Website, Drivers and Downloads, Video category, should resolve this issue.