Computers with no monitor
Why the screen comes out black, and how to fix it.
A computer in a cupboard is a great thing to share. It is also where the black screen problem lives, and the cause is nearly always the same: there is no screen to copy.
Screen sharing reads a real display. No monitor, no picture. This is true of every tool, not just RealFrame.
Give it a screen
Two things cause black:
- No monitor plugged in. Use an HDMI or DisplayPort dummy plug. They cost a few pounds and pretend to be a monitor. This is the reliable fix.
- Locked with no monitor. Windows blanks the display about a minute after locking. Sign in once at the machine, or use the dummy plug.
A game in fullscreen mode can also come out black. Set it to borderless windowed.
Test it before you put it away
Connect to it once from the computer you actually plan to use, while you can still see its screen. A machine that turns out to send black is much easier to fix on the desk than in a cupboard.
Keep it up
- Sleep off, hibernate off. Screen sleep is fine.
- Wired network if you can.
- On Linux:
loginctl enable-linger "$USER"so it survives logout.
Checking on it from afar
Devices shows online state and last seen. Activity shows what it has been doing.
Online there but black in a session? The problem is the screen, not the network.
The login screen
Reaching a computer before anyone logs in is genuinely hard: the login screen is a separate, protected desktop. Support for it is partial today. If you need it, keep a user signed in and lock the screen instead of signing out.