After updating to Catalina, Mac Mini 2018 does not send any HDMI signal.
It was working fine today, until the Catalina update.
Can not enter safe mode nor recovery mode.
Tried resetting NVRAM, no change.
Just in case, I tried another cable and I also tried connecting it to AVR, but still no signal.
Mini is connected to 4K TV, I don’t have any other option (except USB-C to HDMI adapter which I don’t have).
Mac mini 2018 or later
cwanke72 mentioning lower res displays led me to workaround.
I dismissed it at first because I do not have any other displays except Sony 4K TV.
Then I remember Sony has two "30Hz non HDR" HDMI ports.
I connected Mac Mini to one of those, had to shutdown Mini (it was powered when I changed connection) and after I turned it on - signal was finally reaching TV.
Now I need to figure out how to make it work on 60Hz HDR port.
This exact problem occurred on 2 Mac Minis after updating to Catalina. Downgrading to Mojave by restoring from CCC clone did not resolve it. I suspect that Catalina updated some HDMI related firmware which cannot be easily be undone.
i have an active support case open. In the meantime, a USB-C to HDMI cable works fine, as it bypasses the HDMI output on the Mac. https://www.amazon.com/gp/product/B075V5JK36
So I upgraded to Catalina about a week ago on my Mac Mini 2018. I'm driving 3 LG 4k displays (2 via usb c and 1 via HDMI). Absolutely zero issues with Mojave with this setup. Initially everything worked great after I upgraded to Catalina, then just today my mac mini froze and rebooted, and my signal to HDMI was gone. The 2 usb c displays work with no issue, and the mac mini recognizes the display in the HDMI port, but there is no picture. I ordered a usb c to HDMI adapter just this morning (as others had suggested as a work around) it arrived tonight (love amazon) and I plugged it in and it worked. Although there is a big problem...you can't drive 3 4k displays using just usb c on the 2018 mac mini...so only two work at the moment. I've tried all the solutions in this thread, pram, nvram, safemode, smc reset...nothing is bringing back the monitor attached to HDMI. I'm not going back to Mojave, as I've read that also does not work. I'm just stuck hoping Apple releases a firmware or macOS update to fix the problem. I'm still at a loss as to why it was working just fine for a week, then all of a sudden nothing.
Resetting PRAM & SMC took a 3 (4K monitor) setup with the HDMI port not working at all (meaning only 2 monitors working), to a 3 monitor setup working with all 3 monitors running at full 4K resolution at 60hz. Of note the PRAM reset lead to the HDMI working at 1080p but not 4K, then the SMC reset took the HDMI port to 4K 60hz!!!
Using an alternative cable USB-C (Mac Mini 2018) --> Display Port (Samsung U28E850 4k), works with 10.15
Good luck.
Have you installed the latest patch . 10.15.1
. It should cure the problem .
install the update with a USB-C to hdmi adapter which fixes the problem.
after the update completes and the system is stable then power down and back up with the adapter in place and then power power down and go back to the hdmi cable and all should be good.
i had been using the USB-C to hdmi adapter since the the move to Catalina and now that 10.15.1 is install my hdmi port works perfectly .
10.15.1 DID NOT fix mine. I did as others suggested. Reset SMC and NVRAM after updating. Still the same issue. I tried USB-C to HDMI cable, standard HDMI-HDMI cable. Nothing works except connecting HDMI cable to my UDB-C hub with HDMI. This makes no ****** sense at all.
Update: Loaded 10.15.1, cycled power after MacMini stabilized with USB-C/HDMI adapter attached, and switched TV input to the HDMI-direct connection (both from mini) and had video. Powered-off mini, unplugged USB-C adapter from mini & related HDMI input on TV (now just HDMI-direct signal). Turned mini back on and the HDMI signal remained intact. Several sleep cycles later and I still have full HDMI from MacMini (have recycled power 2x also). MacOS 10.15.1 seems to have repaired the issue on my machine.
It may not help but have completed the upgrade with a thunderbolt to DP cable. After that was completed the HDMI output has returned.
resetting pram fixed it for me. and yes HDMI Specific.
Problem solved on my side by updating the firmware of tv + reset smc&pram on the Mac.
FWIW. I had the exact same issue with my 2018 mini and Dell 4K monitor when I upgraded to Catalina. The only "fix" to get 4K @ 60Hz (w/HDR) for me was to use the Belkin USB-C-to-HDMI adapter that I got from the online Apple Store.
I have just gotten off the phone with Apple Tech Support. The case got escalated, and they spend an hour collecting information.
APPLE KNOW ABOUT THE ISSUE, AND THEY CAN REPRODUCE IT.
The reason why they collected all the information, was to get as much as possible.
They are working on a fix, but it'll probably be a while. I am testing Beta 15 (19A582a) which I believe is 15.1 or perhaps 15.2, and it is still an issue here...
So after NOT letting my (late 2018) mini shutdown for several days to avoid the display issues, I've been checking for a software update... well this afternoon it said there was one available. I had it install for 15 minutes, it restarted, and my LG 32UD99-W.AUS is again not responding... black screen, no signal. I unplug the HDMI cord and plug in to the 1080p HD TV, no signal, so I have to hold the power button on the mini forcing a power-off. Power up the mini connected to the TV via HDMI... starts as before.
Reconnect to the LG 4k display and as before it works. Check the update version of the software... IT STILL SAYS 10.15 (no .1)
I used a USB-C to USB-C cable from the mini to the monitor and that seems to work normally giving scaled 4k even after shutdown and restart. I'm pretty sure that didn't work for me when I tried after initially installing Catalina or I would have used it.
So... 1) maybe they partially fixed something. 2) Why an "update" with out a "version #"
It DEFINITELY updated software because it went through the "installing lines" and it had an abbreviated "setting up your mini"
For me and my coworker, every USB C -> HDMI Cable didn't work.
Solution is connecting HDMI Cable via Satechi's hub, using USB C -> USB C Cable (if you have external display with USB C) or USB C -> Display Port Cable.
I'm so tired resetting SMC, VRAM and other stuff like this. Everyday im searching the Internet for solutions posted in last 24 hours but after almost two weeks I honestly lost patience.
IMHO Catalina is not finished and properly tested and we are nothing else than beta testers.
I had the same problem after I finally got it in recovery mode. I have u28e590d Samsung 4k monitor and the only way I was able to get it all the way back to normal was using thunderbolt usb-c to hdmi 2 (60hz 4k(2.0) hdmi) adaptor and I have not had to manually cycle my monitor. You could try an SMC reset if it continues. To be clear, I am using HDMI 2.
No HDMI signal after update
