I upgraded two Dell E6420 laptops from Windows 8.1 to Windows 10. I use both with the same docking station connected to a Dell 2408WFP monitor and a Dell U3011 monitor. The laptops have two display adapters: Intel HD 3000 and NVIDIA NVS 4200M.
Laptop #1 came out of the upgrade working fine -- plug it into docking station and both external monitors work and the laptop screen sleeps.
Laptop #2 won't display anything on the 2408WFP monitor unless I go into Device Manager and disable the Intel HD 3000. But then the laptop display won't shut off (displays blank screen but stays on) and I lose the computer sleep option from the start menu. Enable the Intel HD 3000 and I get back the sleep capability but lose the 2408WFP again.
- Verified Optimus is on in BIOS.
- Updated BIOS to latest version A22.
- Updated NVIDIA display driver. Windows said it was current but I got a more current one from the NVIDIA site.
- Looked for a more current Intel HD 3000 driver, there wasn't one available.
BIOS and drivers are either the same or newer in Laptop #2, and the only other difference is that #2 has Windows 10 Pro while #1 has Windows 10 Enterprise.
EDIT: Redoing the upgrade to Windows 10 resolved the problem, but then after I used the computer off the docking station, when I put it back on the docking station the problem was back. I'm looking for a better solution than reinstalling windows every time I take the laptop away from my desk.