It's a long shot... External monitor / MacBook clamshell mode

[UaeExile]

I've got my MBP hooked up to an external monitor via a thunderbolt cable and for the past six months all I've had to do is wiggle my wireless mouse or tap on the keyboard and the MBP wakes up and the monitor comes on. For some unknown reason it's stopped doing this

Now when I do the mouse/keyboard thingy nothing happens. I've got to open up the MBP, put in my password, wait for it to load, then the external monitor wakes up and I can close the lid and work as normal. This wouldn't be an issues, but my MBP is stored under my desk... So doing it is a right faff.

Does anyone have any ideas what might be wrong? Help very much appreciated

 

[Andy Taylor]

Check the support article on closed-display mode to make sure that everything is as it should be.
Is the Mac plugged in to power?
Are your external devices wired or Bluetooth? If the latter, check batteries.
The machine might be forgetting there's a display attached - try disconnect/restart/reconnect/restart.
Reset SMC and NVRAM
Check the support article on closed-display mode to make sure that everything is as it should be.

 

[Brazo]

I used to have exactly the same issue and the problem was the connection between the mbp and the display out cable had become worn and needed to be wiggled a bit.