Macbook Pro 2nd screen won't wake

Pardon me if this is old hat; I couldn't find an answer by searching.

I have a 2nd VGA screen running off my Macbook. It works fine; but if I let the system go to sleep it won't wake up short of pulling out its plug and reconnecting.

Dragging a window onto it doesn't work, nor anything else I can think of.

No doubt it's a duh, what? type answer, but all newbie help welcome...

Would guess it is a display problem rather than a problem that can be solved by any setting on your Mac.

Tried pressing the power off/on button on the monitor instead of unplugging it?

Thanks for your reply.

bobtomay said:

Would guess it is a display problem rather than a problem that can be solved by any setting on your Mac.

Click to expand...

Well I'm pleased enough that it's not a general idiot answer that everyone knows but me

That would make me think it is indeed to do with the display itself, or everyone would in fact know.

Tried pressing the power off/on button on the monitor instead of unplugging it?

Click to expand...

No effect

Roy Gardiner said:

I have a 2nd VGA screen running off my Macbook. It works fine; but if I let the system go to sleep it won't wake up short of pulling out its plug and reconnecting.

Dragging a window onto it doesn't work, nor anything else I can think of.

Click to expand...

Two thoughts that may or may not help:

1. Do you know if the monitor itself has a separate sleep setting? Many monitors have built-in display adjustments for things like color, contrast, brightness, and many other things. Maybe your monitor has some sort of setting that is preventing it from "waking" up.

2. This is a long shot idea. Not many folks are using VGA any longer (at least with Mac's). Maybe it has something to do with the VGA to Mac connection (versus DVI, mini-DVI, HDMI, mini-display port, Thunderbolt).

- Nick

1. I've pressed loads of buttons on the monitor, to no effect.

2. Telephone support from Apple can't find others with the same problem so yeah it's probably just a 'feature' of the screen I'm using.

Now I really am baffled.

If I restart my machine, the 2nd screen wakes up just like I'd expect; it's only when it comes back from sleep that there's a problem.

This surely must mean that there's something I can do to make it come back to life from sleep, too?

Try resetting the System Management Controller as that determines the status of an external display. Let's see if that cures it. See the following Apple KB article: LINK

Roy Gardiner said:

Now I really am baffled.

If I restart my machine, the 2nd screen wakes up just like I'd expect; it's only when it comes back from sleep that there's a problem.

This surely must mean that there's something I can do to make it come back to life from sleep, too?

Click to expand...

I'm not sure why you're baffled. This thread was about this 2nd monitor not waking from sleep. You never said (until your last post)...that there was any problems when the computer is rebooted.

Personally...I would have expected the external monitor to work fine on a reboot/restart.

Hopefully the SMC reset that chscag suggested will cure things. If not...you could also try an NVRAM Reset.

http://support.apple.com/kb/ht1379

- Nick

pigoo3 said:

I'm not sure why you're baffled. This thread was about this 2nd monitor not waking from sleep. You never said (until your last post)...that there was any problems when the computer is rebooted.

Personally...I would have expected the external monitor to work fine on a reboot/restart.

Click to expand...

Hadn't said because I hadn't rebooted before. And when I did there were no problems with it, the 2nd screen worked fine - rather to my surprise. I, too, would expect the 2nd monitor to work fine on both reboot and restart, or not at all in both cases; it's that it works differently that I am finding baffling.


Forgive me for being a soppy milquetoast but I'm quite reluctant to do what look to be basic system resets on a machine less than 2 weeks old and which I don't really understand. Thanks for your help anyway, I appreciate it.