External Monitor goes black for a few seconds randomly throughout the day

I have the same problem. I tested 2 different Mac Book Pros (M1 and Intel), both with the latest OS Sonoma 14, and 2 USB-C cables. Both have that same issue. I don't use the Parallels Toolbox utility called "Focus on Window" mentioned above. What can I do? It is very annoying.

Ok so I finally fixed my issue after replacing the monitor provided cable with a USB-IF certified cable like this: https://a.co/d/5DO9dQF

Problem gone! I have a Dell UltraSharp U2723QE monitor and M1 MacBook Pro.

I don't have Parallels Toolbox, just running stock Ventura 13.x. with a single display.

My '22 Mini has been doing this out of the box — it came with Monterey, upgraded to Ventura, no change — and I've installed a shareware app called "Amphetamine" which jumps in at boot time and basically blocks out any actions involving screen sleep; this mitigates the problem somewhat, but it still blacks out from time to time.

I'm beginning to despair that this will ever be fixed, ever. I'm being pestered to upgrade to Sonoma, but I ask myself "why bother?". No, really, why should I? Have they fixed this truly, truly obnoxious vile bug yet? It's been doing this since Monterey, it's a bug that affects my work, and I really am feeling ignored by Apple.

I am currently using this https://www.amazon.com/gp/product/B0B5XBYQSM/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 it uses USB power and seems to have some logic built into it, but it doesn't help. Amphetamine is not having any effect on the issue. I might try the USB C cable you suggest, but that would be another case where a pure "USB C to USB C / No Hub" connection is required, as is the case with Pro Audio Interfaces.

Does anybody recommend a solid USB C Hub with Ethernet ? I also need a wired Network Connection due to a long standing issue with WiFi and Pro Audio Interfaces.

alex.carr wrote:

• I have a MacBook Pro 16-inch 2019 that I use with two external monitors. I have a problem with only one of the monitors and it only surfaced recently after an upgrade to macOS Ventura 13.3.1.

Can the system be tested to see if there is a device problem?

The current stable release of Ventura including bug fixes, security updates is macOS Ventura 13.4 —I would start there.

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

See my above reply. I'm using a shareware app called "Amphetamine" which basically disables anything that puts the computer to "sleep". The screen saver will still work, but any other "calls" which put the display to sleep are blocked and disabled. "Amphetamine" has done a fair job of mitigation, but Apple itself is apparently still ignoring us.

I have the same problem. Don't remember when it started, but Ventura 13.3 could be about right. Now I am on 13.6 and it is still happening. I suspected a hardware problem on my ~25 year old 2nd monitor and eventually replaced it with a new one, plus moved from DVI to VGA to HDMI, with new cables thrown in as well. It's still happening! Apparently random, sometimes not for some hours, sometimes 6 or 8 times a minute without rhyme or reason. Not a thermal effect. My computer is a 2017 27" iMac with 40GB memory, which is otherwise doing fine. Can't upgrade to Sonoma - not compatible any more. I am not running Parallels either.

I was having the same issue too. What I found what worked is just keeping my Mac plugged in at all times. Although considered bad for the Mac battery, that's just what I found that worked. Hope this helps.

I have the same problem with a DELL P3421W 34" display and a "14 MacBook Pro 2023 running Sonoma 14.2.1.

I thought it was the display that was defective but started to realize that when I was using a linux machine with it, it NEVER blacked out. DELL were very good about it and I've been through 2 replacement displays to no avail and it happens no matter what input I use - HDMI, Display Port, USB C . It never occured to me that an Apple product would be the culprit. Very disappointing. I will try Amphetamine.

Hi everyone - I have an update.

I have stopped using the HDMI port and switched to using one of the Thunderbolt ports to connect to my external monitor which fortunately has a USB-C display-port input. I am using a high quality 40gbps cable and so far the "monitor randomly going black" problem has gone away. Clearly there is something wrong with the HDMI port.

Cheers.