I have my retina MacBook Pro running a Dell U3011 monitor via the HDMI port. Periodically, the monitor shows an error message:

Unsupported audio format
Please set the audio output on your audio player to Pulse-code modulation (PCM) if available.

People have suggested to use some other method of connecting the monitor to the Thunderbolt ports as a solution and this would work but in my case, I want to run this monitor from the HDMI port. Anyone have any suggestions?

2 Answers 2


Go to the Utilities folder in the Applications folder and open the Audio MIDI Setup application. Select the HDMI Audio Device connected to the Dell U3011 monitor. Configure the audio format to "44100.0 Hz" and "2ch - 16bit Integer". As far as my minimal testing shows, this should fix the issue.

  • I've changed setups once again but I will try this solution next time I have the Dell U3011 attached.
    – wuliwong
    Oct 17, 2012 at 16:31
  • YES! This fixed the problem! Thank you! That stupid message was so annoying! Feb 6, 2013 at 22:46
  • This should be marked as the answer. The problem was driving me crazy (same setup here, two displayport monitors and the third one via HDMI) and the instructions above work perfectly.
    – martona
    Mar 3, 2013 at 0:42
  • I'll mark this as the answer, if it worked for other people. As I said before, I never actually have verified this worked.
    – wuliwong
    Jul 10, 2013 at 4:25
  • Seems to work! Fantastic! The messages was driving me mad, without this fix I would have to ditch the monitors. However, the settings seems to reset after a while, maybe disconnect, logout, reboot, who knows. Any cure for that?
    – stolsvik
    Jun 22, 2019 at 15:01

Try opening up the Sound panel in System Preferences, and making sure something other than HDMI is selected for the output. If that doesn't fix it, try changing the "Line Out Source" in the monitor's Audio Settings. See the details in the manual here.

If possible, you may want to try using Displayport for this monitor, as you're limited to 1920×1200 connecting it via HDMI. Displayport would allow for the full 2560×1600.

  • yea, i'm actually running two thunderbolt displays in addition to this monitor, so this one has to go in the hdmi port. i know, it's ridiculous, but we have all these extra monitors at work. :) The sound is set to my headphones and the line out source option on the monitor is "grayed out". :/
    – wuliwong
    Sep 6, 2012 at 21:14
  • Regarding resolution: .. or you could get hold of the shareware (14 euro) app "SwitchResX" which seemingly does the trick. Currently running 2560x1440@60Hz on a Dell U2711 over HDMI. This is on a recent (early 2019?) MacBook Pro. Had to make a "custom resolution", but once it's made, you also have it in the standard picker in SysPref->Display (hold Option when clicking "Scaled")
    – stolsvik
    Jun 6, 2019 at 13:23

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