External display not recognized after waking from sleep until restarted
I still have the same issue on a macbook pro 15' 2018.
Unplugging and plugging again the screens helps without having to restart the whole thing... except that all open windows jump to the main screen.
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///// EDIT solved the issue through an external thunderbolt dock
I am using the Thunderbolt 3 Dock of Glyph now. My external screen is connected to its Display Port port. After waking up the screens behave normally. When I take a break, I power off the external screen and power it on before waking up the computer. In the tips I got from Glyph, they do ask you to turn off Energy Saving options when connected to the dock, but it all seem to work fine,