Hello, all,
I have a similar problem with a Surface Pro 7 and a Surface Dock 2. I have two Dell monitors (different models) connected via USB-C to DisplayPort. When docked, I usually have the SP7's monitor off and the two external monitors on, like a regular desktop setup.
I restart the computer with the dock attached. During bootup, I see the Surface logo on both monitors. But when I get to the Windows login screen, only one monitor is active. When I log in, I see that Windows thinks the second monitor is there (for example, the wallpaper is stretched across both), but is not sending a signal to it. (This issue does NOT occur when the PC is put to sleep then woken up. In that case both monitors wake properly.)
Undocking and docking the device does not fix the problem. Undocking the device, changing the orientation of the Surface Connect connector and redocking does not solve the problem.
Unplugging the dock from mains power and plugging it back in after a few seconds (without undocking the PC) solves the issue.
Pretty irritating.
Any help would be appreciated.
Andrew