I've got the following config:

Windows 7 with dual monitors on a DELL Optiplex 7020

When I'm leaving my screen for an hour or so and after I get back, the first screen refuses to "get back to work" giving me a black screen instead. My second monitor displays everything.

I found the following workaround

  1. On my second screen, duplicate the monitor on both screen

  2. Once done, first screen is ocassionally displaying

  3. On the second screen, I extend the monitor to both screen

  4. Read point 2

  5. Repeat point 1 to 3, two more times and voilà, I have display , again ,on both screens

As I said, this is a workaround e.g. it should be temporary and the workaround costs me time (10 to 15 mn to warm up my screen)

I parsed the internet but found nothing relevant so far.

My question is the following:

Have you seen soemthing similar and if yes, how did you fix the issue?

Maybe it is the cable but I'm unsure of that.

Any hints or ideas are more than welcomed

Update 1: I ask my colleague for some help. We changed the frequency, but to no avail...

Update 2: I unplugged the HDMI cable and replug it to another HDMI port. The screen started...without any delay, just like that

Update 3: The long night sleep is the Test. It did not work out. What I have done so far: Update the 2 screens drivers, update the video drivers but the PC said they were already brand new. It does not seem to be the cable. We don't have a spare one, this is the issue.

  • Does your display have multiple input connectors and an input selection button?
    – Daniel B
    Feb 27 '16 at 16:30
  • Hi @DanielB , no multiple input connectors and no input selection button
    – Andy K
    Feb 27 '16 at 16:32
  • Questions: (1) How are the monitors connected and what is your display card? (2) Is Windows fully patched especially drivers found as optional in Windows Update? Remark: You could create a script to do these display manipulations using DisplaySwitch.exe in a script run automatically on wakeup.
    – harrymc
    Feb 27 '16 at 19:53
  • It sounds to me like the graphics card is only waking up one monitor instead of both. Is your optiplex the version with the intel built in GPU or do you have a standalone video card? And if so, how are they physically wired (that is, one monitor connected to the mobo and the other to the video card? both to the video card? something different?)
    – taltamir
    Feb 28 '16 at 21:38
  • we had this issue at an old comany I worked at. What cables are you using display cables are you using (VGA, DVI, HDMI)?
    – Lelantos
    Feb 29 '16 at 17:42

The problem is evidently related to HDMI and might have something to do with your particular hardware configuration and drivers.

While you have already done all the evident steps, such as updating all drivers, you could still see if Windows Update has any driver updates in the Optional section, or recheck the driver downloads on the manufacturer's website.

You could also try a different adapter+cable combination, such as HDMI to VGA (or DVI) adapter, which might help by changing the hardware/driver configuration. Avoid using the DisplayPort because it also has sleep problems on Windows.

If this fails, you could check Windows for errors by doing sfc /scannow, or take the big step of doing Repair Install which will in effect reinstall Windows while conserving your applications.

If you don't feel adventurous, a workaround might be to run a script automatically on wakeup which will do the manipulations that currently take you 10-15 minutes. The tool to use is DisplaySwitch.exe that can be called with the following parameters :

internal : Switch to use the primary display only
external : Switch to the external display only
clone    : Duplicates the primary display
extend   : Expands your Desktop to the secondary display

Search for "dell cab files" to get the latest drivers directly from Dell. http://en.community.dell.com/techcenter/enterprise-client/w/wiki/7457.optiplex-7020-windows-7-driver-cab
I have had the same trouble and had to do a factory reset my monitors. Be sure to check that all cables are seated and haven't wiggled loose, even a little. If the video is provided via a video card and not on-board you might try re-seating the video card. Before you re-seat the video card be sure to have the drivers downloaded. I have had bad luck with updating video drivers from Windows Updates. BTW you unzip cab files, if you haven't messed with cabs before. If all that doesn't work, try another monitor if you have one available and see if it is really the monitor or the machine.

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