How to keep displays on / turn them on, when disconnect / reconnect USB-C Thunderbolt

[oyvindbjo]

I have some issues turning on my two displays (4k Dell P4317Q and 2560x1440 Dell U2715H) when connecting my laptop to my HP Elite 230W Thunderbolt Dock. 50% of the time it works, but sometimes only one or the other display turns on, or none at all. When the display(s) don't turn on, Windows say they are all connected, and I can move the mouse into the display, withoug seeing the cursor.... When it fails, I can reconnect the USB-C cable, then sometimes is works and sometimes the display  that didn't turn on is turned on while the one that worked turns off, or both off.

Even though i connect the docking cable before power on, I also get the same problems.

This seems to be totally random, I havent been able to find any pattern or dependencies on how/when I connect/power on...

Anyone know how to fix this?

[oyvindbjo · Accepted solution]

When I bought the HP Elite 230W Thunderbolt Dock, for some reason, I was not able to update to newest firmware. During the last two monts there have been several driver updates on my laptop that might have fixed some dependency issues. One week ago the FW update "sp98906.exe" was successful. There have not been any issues with the display(s) not turning on since.