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When unlocking a Windows 7 computer the screen briefly (less than a second) goes blank before showing the screen (this is normal). Abound once a month (but sometimes within 24 hours) when I unlock my computer the screen doesn't come back from this brief blackout and stays black. Sometimes after five minutes or so the display will come back. Other times it has been blank for over 20 minutes, so I give up and restart the computer.

  • It seems to happen more often when the computer has been locked for a longer period of time - I lock my computer several times a day, but the problem most happens when I come in at the start of the day.
  • I have updated my video card and monitor drivers.
  • I have two NEC AccuSync 75F monitors both driven by an ATI Radeon HD 2400 Pro.
  • The computer is a Dell Optiplex 740.
  • When the problem occurs both monitors have a green light on to indicate that they are receiving signal.
  • I've tried unplugging the monitors from the video card and turning the monitors on and off.
  • The screen saver is set to one that is not blank screen.
  • The Windows power settings are set to never turn off the display.
  • When the problem occurs there is no significant disk activity occurring.
  • When the problem occurs I can connect over the network to the hard drive on my computer.
  • When the problem occurs I can't connect over the network with a VNC connection. The VNC client doesn't give an error, but also won't show the screen. The task actually seems to hang as I can see the task, but there is no window for it.
  • This problem occurred when I was running a pre-release version of Windows 7. The hard drive was formatted for release version and the problem still occurs.
  • I've been stopping some of my always running programs to see if one of them may be the culprit, but given the span between failures that will take some time to find the problem if it will even help at all.
  • Some programs I have always running include IE, Firefox, Outlook, Evernote, Kana Reminder, Ditto, Macro Express, Timesnapper, and DisplayFusion.

Any ideas appreciated.

Leigh Riffel
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5 Answers5

4

I've encountered the same issue. For me, TimeSnapper turned out to be the culprit: if I remember to disable TimeSnapper before locking the desktop I never have a problem.

poco_forte
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Thanks for such a comprehensive report of the problem! I was seeing a similar problem on my Dell Optiplex 755 computer with a Dell LCD display and NVIDIA Geforce 9800 GT graphics card. It used to happen when I came back and unlocked the computer. After typing the password to unlock, it would lead to blank screen about 1 out of every 3 times!

I suspected that it might have something to do with the display utilities. I was using Dexpot as my virtual desktop manager. I uninstalled it a week ago and have not seen this blank screen problem after that. Maybe you want to uninstall any display utilities you are using for virtual desktops or for dual displays.

Ashwin Nanjappa
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Just wanted to add that I have the exact same symptoms, with no known resolution. I've had a terrible time finding web pages about this particular symptom set, because usually they're about the "black screen of death" where the mouse is moveable and/or the task manager is running. It's good to know I'm not the only one.

A few details:

  • It only seems to happen with my wife's user account, not with mine. I did all the original installation under my account, but she is configured as an administrator, so that shouldn't matter.
  • This started happening sometime a year or more ago. I just last week did a clean reinstall of the OS (Windows 7 Home Premium 64-bit) and it is happening to her again. I copied a bunch of her user data (manually, folder-by-folder) over from the old installation, but nothing that should be involved in the login process (as far as I can tell).
  • Our computer is a custom-built machine, unbranded. The one common component with your setup is we have two ATI Radeon 4850 Pro video cards (in Crossfire) installed. We also have an SSD, but the one in now (an Intel) is actually a replacement for the original one (a $%^& G.Skill), and the problem happened with both. I have upgraded all drivers for all the hardware.
  • The problem doesn't seem to happen if I just create a clean user account, but it's hard to be sure because the problem is so intermittent that it might just be that we don't see it on the few times we try logging in to the clean account.
Nathan Arthur
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0

We have a Windows 7 Thinkpad X200 tablet that does this all the time too. We updated the Lenovo power manager and a few other drivers and tweaked the power settings a bit. We did have a Corsair SSD in it. Does your system match any of these variables?

Elijah Lynn
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There are numerous other questions with similar issues: Windows 7 Black screen of death and also Why does my Windows 7 boot up to a black screen after login? just to point to a couple.

This happened to me also where Win7 incorrectly identified my video card and installed the wrong driver. The majority of instances I've heard of (though not all) also had the issue being an incompatible or incorrect video driver. In other cases it was another device driver that was either not really Win7 compatible or incorrectly identified.

Community
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BBlake
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