11 Replies Latest reply: Jul 3, 2014 2:12 PM by BDAqua
tinue Level 1 (10 points)

I have a Mac Mini 2012 model, and an HP ZR30w display. They worked fairly well together, using a Display Link -> Display Link Mini cable plugged into the Thunderbolt connection.

Even while this combo worked I had wake-up issues, in that the screen remained off until I unplugged and replugged the DisplayLink cable.


Then all of a sudden I could no longer log in: The Mac booted until I could click my user, and after entering the password I saw the eternally spinning color wheel. When I used another display via DVI, everything worked as before.


Now, a few days later, the Mac crashes almost immediately. Sometimes I get until the logon screen, but then the Mac reboots spontaneously. As before, a DVI connected display works fine.


So my question is: How can this be? The display can obviously be detected and used, otherwise I couldn't see the logon screen. What exactly is causing the later reboot?


Thanks! Martin

  • lllaass Level 10 (175,857 points)

    Reset the NVRAR/PRAM and SMC

    Intel-based Macs: Resetting the System Management Controller (SMC)

    About NVRAM and PRAM

    Does it happen with if booted in Safe Mode (limited number of drivers loaded)

    Have you updated to 10.9.4 (it was released yesterday)

  • tinue Level 1 (10 points)

    Thanks for the suggestions. Yes, I performed a reset of NVRAM, and indirectly also of SMC (I had the Mac Mini unplugged for a while while looking for answers).

    It happens in safe mode, and it even happens when I try to boot from a different medium (hold down the "option" key). So it must be something pretty low level.


    I am ready to accept that the display is broken, but I still wonder what it is that crashes the Mac in this way.

  • Drew Reece Level 5 (6,251 points)

    It's possible it could be the adapter? You are still using that?

  • tinue Level 1 (10 points)

    It's not an adapter, just a cable with a Display Port connector on one end, and a Mini DP on the other end. But to make sure I replaced the cable; Unfortunately this did not change anything.

  • Drew Reece Level 5 (6,251 points)

    That's frustrating.


    It may be worth running Apple hardware test when connected to either display. If you are lucky a cryptic error may be able to help diagnose something.

    Using Apple Hardware Test

  • tinue Level 1 (10 points)

    Wow, there is a lot hidden in the little Mac... I never heard of the hardware test before. It ran through on either display, without an error message.


    After restarting, the HP display works as before. I can't explain why.


    The only theory that I have is this:

    Because I couldn't initially reach he hardware test, I again unplugged the Mac from power for a Minute, and then replugged it. This would have once more cleared the SMC. Also, I unplugged all USB devices. They are now plugged back in and it still works, so I don't know if this was part of the resolution.


    I'll give it another day or two, and then mark my question as resolved.

  • Drew Reece Level 5 (6,251 points)

    This is just weird.

    I'd backup the internal disk just incase the hardware is failing, it probably isn't but I'm cautious .

  • tinue Level 1 (10 points)

    Yes, weird indeed.

    Time Machine runs regularly, so at least my user data is protected. Full image backup seems to be impossible on a Mac, at least with a fusion drive.

  • Drew Reece Level 5 (6,251 points)

    I believe you can clone the data within a Fusion drive volume, the recovery partition & the logical volume structure isn't copied as far as I know, but you should be able to make a clone of the filesystem.


    Carbon Copy Cloner can do this…



    I suspect SuperDuper! and Disk Utility may also be able to make a clone.

  • tinue Level 1 (10 points)

    For those that are interested: The culprit was a USB card reader plugged into an USB 3 hub. When this device is connected, I can't login as I described in my first port.

    Most likely the later plug/unplug damaged the cable, so that I got the further issues when the display didn't even light up.


    Indirectly, the posting about running the hardware test pointed me into the right direction: Before the test, one is told to unplug all USB devices. I did this, and everything was fine. Today, I finally replugged everything and it stopped working. A few trial and errors later I knew which device was to blame.


    After boot I can use the card reader, though, so it is not a big issue for me.

  • BDAqua Level 10 (122,237 points)

    Whew, great work, thanks for the report!