I have a Mini late 2012 (i5 16GB RAM). It was running Mavericks and now running the Yosemite Beta. A Dell U2414H and an older Dell E207WP

My problems is:

My Dell U2414H randomly says there is no signal and goes black. The only way to get it back is to reboot my Mac. This happens randomly, it could happen 10 times in one hour or once in 2 days. I have the monitor connected via Display Port to my Mac's Thunderbolt connection. My other monitor (E207WP) is connected via HDMI to DVI (woks fine).

This problem started on Mavericks and continued to Yosemite. I have performed clean installations of each but the problem persists. I do not have any other computers available to test the monitor on.

I have ordered a few Display Port and HDMI cables from Amazon hoping that will help.

If anyone has any ideas I would really appreciate the help. Restarting my Mac all the time is killing my productivity.

  • My guess would be that the video card is failing. Does it tend to fail when you are working it hard?
    – AllInOne
    Sep 23, 2014 at 22:32
  • No I could be sat looking at my desktop with nothing but chrome open. My monitor connected via hdmi to dvi works fine. It's just the one connected to thunderbolt
    – Steve
    Sep 24, 2014 at 7:17

2 Answers 2


Maybe the problem is caused by overheating. When I put a pot filled with cold water on top of the mac mini, the blank screen problem occurs less often.


I turned off hard disk sleep and now it's fine.

  • It would be helpful if you could add more detail to your answer including instructions for how to turn off hard disk sleep.
    – grg
    May 22, 2018 at 9:39

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