Mac to Samsung TV via HDMI and “Mode Not Supported”

I’ve had a Mac Mini hooked up in my living room and being used as an HTPC for a while now.  However, as the Mac Mini doesn’t have HDMI-out, I wasn’t able to get it set up as I really wanted, which was to have it going through my receiver as HDMI and just use the receiver to switch between my various home theater components.  That is, until I found an adapter at Monoprice that takes the mini-displayport and USB outs on the Mac Mini and combines them to output a normal HDMI signal with integrated audio and video.  So, I immediately ordered one.

When it arrived, I went to set it up and then turned everything on.  VoilĂ : I was getting a signal via HDMI!  But it didn’t look too good, so I changed the resolution on my Mac Mini and immediately got a “Mode Not Supported” message on my Samsung TV (PN50A550, specifically).  Rebooting did nothing.  Booting in safe mode worked and let me change stuff, but as soon as I booted normally, I’d be hit with “Mode Not Supported” again.  I searched online.  And searched.  And searched.  I just couldn’t figure it out.

The official information I could find on the Samsung site stated that the “Mode Not Supported” message would appear when the signal the TV was receiving was for a resolution or refresh rate that exceeded the TV’s capabilities which makes sense, of course.  But my Samsung is a 1080p TV and every time I did a safe boot on the Mac Mini, I verified that the resolution was right (1920x1080) as well as the refresh rate (60Hz).  So that couldn’t be the problem, right?  Actually, it was.  See, apparently, the Mini was trying to be too smart and it handles the display properties separately between a normal boot and a safe boot in addition to trying to be smart and detect the settings for the display the computer is hooked up to.  Which is actually really awesome until it detects things wrong or chooses the wrong settings and makes its signal out unusable.

I finally stumbled on this blog post which gave me the info I needed to actually fix things.  The trick is that I had to log into the Mac Mini remotely and look at the computer settings while it was booted normally (not a safe boot).  Luckily, everything you need for that is build into OS X.

Prepare the Problem Mac

  • Boot the problem mac in Safe Mode (or connect a different monitor that will allow you to use the computer) and under System Preferences > Sharing check the option for Remote Management.  For my own setup, under the “Computer Settings” button on the right of that screen, I also had to choose “Anyone may request permission to control the screen” and “VNC viewers may control screen with password” and then set the password.  You may not need those settings yourself, so I’d try without them first.
  • If you have the Mac’s firewall active (and you should!), make sure that “Remote Management” is allowed under System Preferences > Security > Firewall in the “Advanced” section.
  • Make note of the problem mac’s local network IP address, which you can find under System Preferences > Network.  For instance, mine was 192.168.1.6.
  • Reboot the problem mac normally or reconnect it to the TV.  You’ll still see the dreaded “Mode Not Supported”.

Use a Second Mac to Make the Fix

  • Fire up another mac on the network and start the “Screen Sharing” application.  This was really easy for me as I use QuickSilver, but if you don’t, it’s apparently very difficult to find as an actual application.  The simple way to access it is to actually just start up Safari.
  • If you launch the Screen Sharing app you’ll be prompted to enter a “Host”.  Either in that Host box or in Safari’s normal address bar, type in vnc://192.168.1.6 - using the IP address for your own system that you noted above.  You may be prompted for a login, depending on how you set things up.
  • You should now have a screen sharing window that displays the screen of your problem mac, which you can now access and control.
  • While controlling the problem mac, go to System Preferences > Displays and set the resolution and refresh rate correctly.

When I got to this point myself, I finally found the actual culprit that was causing all the trouble.  For whatever reason, the Mac Mini was auto-detecting the display and setting the refresh rate to “50 Hertz (PAL)”, which is incompatible with my own NTSC television (hence “Mode Not Supported”).  Once I changed it to “60 Hertz (NTSC)”, the computer immediately appeared on the TV and everything worked.

Now, while I used a second mac to do the screen sharing, from what I’ve read you should probably be able to do it via any computer type (i.e. Windows, Linux, etc.) so long as you use a standard VNC client.  Hopefully this will be useful to others who encounter the dreaded “Mode Not Supported” message on their Samsung TV when using a Mac Mini (or other Mac).

Comments

Do I need to have the Mac Mini plugged into hdmi when changing modes?

I had my Mac Mini hooked up via the HDMI setup the entire time, Stephen.  I set up the remote sharing settings while booted in Safe Mode displaying via HDMI and then used the screen sharing on my Powerbook to actually make the changes on the Mini.

Basically, the important thing is to get the remote sharing set up, hook up the Mini via the connection type you want (HDMI in my case) so that you’ll be adjusting the settings for that connection type, and then use the screen sharing/VNC to actually make the changes to the settings.

Perfect instructions to fix my problem.  You are a lifesaver.  Thank you, kindly.
*matthew

Bollocks

sorry this is way out there. My mac mini has worked with My 1080 sony tv for 2 years straight into my Tv via HDMI The problem lies with Samsung For F sake my new tv is only 720

I’m sure you’ve resolved this by now, but since I found this thread high up in Google search I thought I’d share another solution I found.

The problem really does seem to be the TV capabilities. I have a 43” Samsung 720 plasma connected to a Mac Mini via HDMI. When I was screwing around with settings, I chose the wrong one and got the “mode not supported” problem.

The easy solution I found was to power down the Mac (hold the power button for 10 seconds), switch the HDMI cable from TV input 1 to TV input 2, then restart. The TV seems to figure things out in maybe a sort of default startup mode. The resolution may still be jacked-up. I went the safe route and just selected 720p in the display settings.

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