my external monitor isn't working since the latest system upgrade. is anyone else having this issue? is there a remedy?

Final Update:

I went ahead and opened a support case with Apple.

We reset NVRAM and also SMC with no positive results.

Then we connected the HDMI cable to a TV and it worked fine!

The final result was we believe the USB-C Hub adapter I am using is intermittent when paired with the monitor. We did get the monitor to work by unplugging all cables from the monitor, including the power cable and waiting one minute. Then plug it all back in, and it works! At least for now. It has been working 1 out of 10 times lately. I tested disconnecting and connecting and it worked 5 times in a row.

Neither myself nor the apple support agent think it is the monitor at fault since it is only about a year old.

She recommended that if the problem comes back with the monitor being black, to purchase an adapter which has been tested and is proven to work with my specific Mac, at this website.

Be sure to select YOUR Mac from the Mac Compatibility list on the left to be sure you select an adapter which has been tested with your Mac.

I hope this information helps anyone else that is having external monitor issues with their Mac.

Abbreviations can be troublesome on a forum like this one where all Readers do not share the same background. For example, how does AOC (the progressive Representative from New York) figure in your display problem?

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What model-year Mac, and what screen size?

what display make&model?

EXACTLY how is it connected to your Mac? mention every cable and every adapter or dock.

Hello, Can you please help? My external monitor is no longer working from my MacBook Air. It has worked for over a year, and now all of a sudden it has stopped working. Occasionally, I can get it to work by rebooting the Mac, but only about 1 in 10 times. The monitor stays black and will occasionally say 'no input'. The monitor on the Mac has the normal display, and it will blink and go black about every 30 seconds. It stays black for about 2-3 seconds. This makes it very frustrating to use the Mac.

I checked the Visio website and there are no driver updates available for Mac, only for Windows.

There are also no monitor firmware updates listed on the website for the monitor.

It is very frustrating and I really need this to work, as I use it for my work.

Here are all of the specifics which you have requested from other posts on this topic:

MacBook Air (Retina, 13-inch, 2020)

Built-in Retina Display

13.3-inch (2560 × 1600)

BigSur 11.6

ViewSonic VX2452MH monitor

Using HDMI input into the monitor

Connecting from the USB-C port on the Mac, thru a USB Type-C Hub Pro

USB Type-C Hub Pro

Mfg: FlePow

Model UCN 3281

Connecting a HDMI cable from the USB Type-C Hub Pro to the HDMI input on the monitor

Two things come to mind as potential issues:

• If that dock uses DisplayLink Drivers, the DisplayLink drivers may need an update. My initial look did not suggest DisplayLink Drivers are used (these are ALWAYS matched with custom DisplayLink chips in the Dock).

• If the HDMI cable you are using is not highest quality, it may be generating occasional error. MacOS software has been increasingly looking for these errors and increasingly fussy about displays that throw errors, and could be deciding, "not good enough".

The cables you want for HDMI-only Monitors (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard TV set, and not much more.

@Grant Bennet-Alder

Thank you for you reply.

I checked on the FlePow adapter and it does not require or provide any software/firmware updates.

The HDMI cable I was using was a High Speed HDMi with Ethernet.

I went and purchased a Premium High Speed HDMI with Ethernet, and unfortunately it DID NOT solve the problem.

Does anyone have any other ideas?

Thank you for any suggestions!

If you upgraded to Big Sur you may have compatibility problems. Check the maker's website and if upgraded to BS look for upgraded BS specific drivers.

What model-year Mac, and what screen size?

what display make&model?

EXACTLY how is it connected to your Mac? mention every cable and every adapter or dock.

Updated to version 11.6. Everything worked last night, today- no external monitor, had to reconnect printer. Monitor is not even recognized. Checked AOC site, nothing BS specific.