Mac mini External Screen - TV Doesn't "Work" based upon Resolution / Output / Refresh

Question

Mac mini External Screen - TV Doesn't "Work" based upon Resolution / Output / Refresh

Mac mini (Late 2014) running MacOS Mojave 10.14.16, and running off an external SSD.

Since purchasing this unit in 2015, we have used an LG Monitor via the HDMI output without issue. Recently we received a discarded TV which is larger, so we set this MacMini up for TV / Streaming purposes in a living room. At first the TV worked, except I couldn't see the menus / icons, so I figured out I had to underscan. No problem. However at some point, it seems I might have changed a setting because the TV now kicks out a message that it's not compatible with the output / resolution / refresh rate fed from the Mac. Ironically I can't turn the TV back on to check the settings. When I plugged the old one in (the LG), it only gave me the settings for that one. I tried reboot, safe mode etc. without any change. So I bought a Thunderbolt/HDMI Adapter and now I can have two screens, which allowed me to manipulate the settings of the TV. So problem solved right? Well, not quite. Oddly I am typing this using the TV as my screen, plugged in via the Thunderbolt, however the second I unplug the HDMI LG, I get the error message again. I've tried restarting and taking the TV to the HDMI port direct, and still get the message. Am I missing something? Do I need to do a Safe Mode restart again, and what would the look like? Many thanks.

iMac 27″, macOS 10.12

Posted on Feb 24, 2024 6:19 AM

Reply

Answer 1

Top-ranking reply

den.thed

Level 10

95,686 points

Feb 24, 2024 8:00 AM in response to mattfromcanada42

Connect only the larger TV and reset the Mac mini's NVRAM to see if that helps.

see > Reset NVRAM on your Mac - Apple Support

If that works, check and jot down the Default Display Preferences for that TV.

Also keep in mind that Mac's do not do well with long cheap HDMI cables. So it maybe in your best interest, to move the Mac mini closer to the larger screen TV and use a short premium certified HDMI cable.

Reply

Answer 2

BDAqua

Level 10

251,309 points

Feb 24, 2024 3:16 PM in response to mattfromcanada42

If the LG & the TV have ports other than HDMI, use those instead, HDMI is the flakiest of all.

Reply

Answer 3

Feb 24, 2024 10:03 AM in response to den.thed

Unfortunately that didn't work. I tried every setting available on the TV. I restarted to the Mac's internal Hard Drive, and the monitor works okay for that. When I did that, I did note the settings and they are the same settings I'm using on the SSD version. It's only when I boot up on the external SSD (a requirement for speed, and the one I've updated / actively use) that it doesn't work, and it only doesn't work when it's the only display plugged in. I have both plugged in now, and I am actually looking at the screen, and typing on the one that "isn't compatible" when I have it stand alone. I really don't get it lol. I am wondering if there is a step I need to ensure I am doing when I reset the NVRAM to ensure I'm resetting it as applicable to the SSD (I don't think that's a thing b/c isn't NVRAM hardware vs software?). I also changed the HDMI cord with no change in results. And unfortunately, it's not practical to have both screens just setup going forward.

Reply

Mac mini External Screen - TV Doesn't "Work" based upon Resolution / Output / Refresh

Similar questions