MacOS – Macbook Pro cannot automatically detect external monitor automatically after I unplug external monitor when it is sleeping

displaymacbook promacossleep-wake

My late-2013 13'' (Retina & OS X 10.9.4 (13E28)) Macbook Pro can not automatically detect external displays after wakes up, if I pull the display‘s plug out during sleep.

1) connect Macbook to my dell display

2) put Macbook into sleep state via apple menu

3) pull the display's plug out while Macbook is sleeping

4) wake up Macbook

After these procedures above, My Macbook cannot automatically detect the remove of external monitor. The Arrangement option card is still there in Display section of the System Preferences and the cursor can still move out of the edge of internal screen just as the external monitor is connoted.

When I then pull the plug and plug it back in, it finds its old configs and fixes the arrangement. Also, I can manually click Detect Displays to fix this problem.

I have tried to reset SMC and PRAM but doesn't work.

By the way, if I check Mirror Displays checkbox in Display Preferences after I weak up my Macbook from sleep, the system will halt and automatically reboot. I think the reason which causes reboot is the conflict between the system tries to mirror display and there is no one external display.

Does anyone experiences the same issue?

I apologise for my poor English…..

Best Answer

I have the same behaviour with exception of the Automatic reboot (it does not do that).

I explain it this way.

When going to sleep mode Mac will create a Sleep image of the system status/configuration.

It is not monitoring the external devices during the sleep.

If you disconnect the monitor during the sleep it will not know that.

When it wakes up it will load the sleep image containing the system profile and is looking for the monitor and can not find it.

So far everything is normal.

I do not know why does it reboot on Mirror Display? For that please provide the Console log at that time stamp so we can look ofr the reason.