I purchased a Dell UltraSharp U2715H. This has a 2560x1440 resolution.

I have a MacBook Pro Retina (early 2013). I now have the following issue getting to this maximum resolution.

1) HDMI If I attach the monitor through HDMI I only get a resolution of 2048 x 1152. I first thought it was the HDMI cable so I bought a new one, no effect. When connected through HDMI everything else (close lid etc) works perfectly.

2) DisplayPort cable The Dell also came with a Mini DP to DP cable. If I use that cable it works perfectly when I startup the MacBook from scratch. So, the beautiful full resolution of 2560x1440 is there! HOWEVER, when I close the lid or the MacBook goes to sleep it somehow "loses" the monitor. The Mac still thinks the Dell is there. It is there in the menu and you can even go with your mouse to the second monitor, the Dell itself however remains completely black. So the only way of getting the monitor to work again is fully power off the Mac and then power it on. This is of course not a workable situation.

So, does anybody now how to solve this, either through a working HDMI or a way to get the DP connection to work normally.


1 Answer 1


The early 2013 MacBook Pro models only officially supported an external resolution of 1920 x 1080 pixels (via HDMI) or up to 2560 x 1600 pixels (via Thunderbolt).

So, in terms of your first point about your HDMI connection, you're doing better than Apple's official specs.

As far as your second point, it's unclear to me whether you're trying to use the MacBook Pro in clamshell mode or not. I'm going to provide some generic advice that should help, but if not you may need to clarify your question. I'm also assuming your Computer is connected to a power socket and not running off battery.

I would reset both your NVRAM and your SMC. See below for instructions.

Reset your NVRAM

Newer Macs use Non-Volatile Random-Access Memory (NVRAM). It may be worth you resetting this. Here’s how to:

  1. Shut down your machine. Yes, a full shut down, not just logging out.
  2. Press the power button and then press the commandoptionpr keys. You have to make sure you press these keys before the gray screen appears or it won’t work.
  3. Hold those keys down until your Mac reboots again and you here the startup chime.
  4. Let go of the keys and let your Mac reboot normally.

Note: When you log back in you may need to readjust some of your system preferences (e.g. mouse speed, time and date/timezone, etc).

Reset the SMC

Your computer's System Management Controller (SMC) can also be reset. To reset this on your particular MacBook Pro, here’s what you do:

  1. Shut down your computer
  2. Keep the power cable plugged in.
  3. Press at the same time shiftoptioncontrol (on the left side of the keyboard) and the power button
  4. Let go
  5. Turn your computer back on with the power button.

After doing both these, let us know how you go.

  • Yes, thank you very much! I already tried the first thing, but the reset of the SMC (whatever that does) seem to have the trick. Great.
    – Arnoud
    Dec 14, 2016 at 8:45
  • Unfortunately, it appears that it is not 100% solved yet. When I use the MacBook without the monitor (in/out sleep) and then after a day come back to my home station and plug it in the DP it reverts back to the old behaviour. If I then do the SMC reset (still no idea what this actually does) everything seems to be OK. But....
    – Arnoud
    Dec 15, 2016 at 14:29
  • Just a wild thought: I am using the cable that came with the Dell monitor. Can it be that an Thunderbolt cable from Apple makes a difference?
    – Arnoud
    Dec 15, 2016 at 14:30
  • Okay, to be able to help you further I really need to know what version of macOS you're running? Also, is your MBP the 13" or 15" version? (They came with different graphics cards!)
    – Monomeeth
    Dec 15, 2016 at 23:52
  • Here you go: macOS Sierra version 10.12.1 (the newest I think since I always press all update buttons...).
    – Arnoud
    Dec 16, 2016 at 9:52

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