MacBook Pro Retina external display problems & resolution

I’ve just spent an entire afternoon messing around with my MacBook Pro Retina trying to get it to work with multiple high resolution monitors and I thought I’d share my misadventures here so that other people may benefit from what I’ve found out..

I run my 2013 MacBook Pro 15″ retina in two different offices both with two external Dell 2711/2713 displays.. I love all that extra space…

Today, I tried to connect up a third 24″ display also from Dell using a new cable and all hell broke lose.. suddenly ALL my monitors were stuck in HDMI modes making it impossible to select their native 2560×1440 resolution. It took me three hours to figure out how to change things back.. so this is what I’ve found.

The 2560×1440 resolutions were gone from the Display Preference Pane and I was stuck on 1080p and the screen mirroring kept coming on.

Things to try:

1. Zap PRAM

There’s actually no longer any PRAM in Macs, but the newer NVRAM works the same. The NVRAM stores some basic system settings including the screen resolutions of attached monitors.

So just shut down your Mac, press the Power button, hold the Command, Option, “P” and “R” keys (before the gray screen comes up) and keep them pressed until you hear the chime once.

No luck, the screen resolutions weren’t back.

2. Zap the System Management Controller (SMC)

In theory, this shouldn’t be necessary, but it’s another standard step in rectifying “weird” behaviors, so I went ahead anyway.

Shut down your Mac and start it up by holding down the Shift, Control, Option (all on the left side) and Power keys.

Still no change. So I spent an hour playing around with SwitchRes X, which is the step that I should have skipped.

3. In the Display Preferences Pane, Option-Click the “Scaled” radio button..

Suddenly all resolutions appear and you can choose whichever you want, not just the ones deemed “safe”. Hurray!

Except there still isn’t the the 2560×1440 resolution I’m after..

4. Finally, switch off the monitors while connected to the MacBook and pull their power supply cables, wait a few seconds, then reconnect the cables, switch the monitors back on and do the option-click trick.. hurray!

The 2560×1440 resolution appears and everything is fine again.

Obviously as always with this type of problem, who knows which bits are optional and which are necessary? It’s possible that if I had known about the Option-click trick and having to switch the monitors off, it would have worked straight away without a single reboot.

I’d recommend pulling the power supply cables of the monitors and trying the Option-click trick first before restarting anything. It does appear like the problem was that the monitors defaulted into some kind of “safe” mode where they don’t show any non-HDMI modes.. but as always: who knows?

I hope that somebody will benefit from this mini-report.

Best regards,