MacBook Pro only Charging when Turned Off

My MacBook Pro (2012, Retina) will suddenly not charge when it's turned on.

If I shut it down, it charges normally (orange led, goes green when full).

After I turn it on it keeps the green led on until OSX starts up, then the light goes off.

I haven't seen anything suspicious in the console. I also did a PRAM/SMC reset.

OSX 10.8.3

Solution 1:

I had the same problem and have tried everything, with no result. Suddenly, I reset the SMC without turning off the MacBook Pro, i.e. with the MBP on and the charger plugged, I hit Shift+Ctrl+Alt+ON for ten seconds (the MBP switches off instantaneously). After restarting, the mac was charging properly.

Solution 2:

I went to Apple Support and even though it looked like a software issue, they just exchanged the power supply and now it's working perfectly again.