10.15.6, external display problem

This is a User-to-User Support Community.

W hen you post that you have checked this against multiple different VGA displays, and all did not work, it leads me think that VGA displays are your preference for daily use, and that is what my reply was about.

If you "'don't see my comments helping to resolve this issue in any way", I invite you to use the Contact Support link at the top of any Forum web page and complain to an Apple employee rather than having a discussion with other Users who sometimes have insights into such issues.

Tried safe mode and didn’t make a difference. Tried all the ports on the MacBook to no avail. It sees the monitor and is trying to connect but cannot.

I would tend to agree. It’s very strange for me in that I know the monitor works fine and the computer can recognize that it’s there but it just cannot establish the connection.

Don't expect any fix from Apple any time soon. Customer support with tell you to drop your laptop at a store and come back pick it up in 3 weeks.

Right on, Karen!

SUCCESS! (?)

Well, I broke down and purchased a USBc to VGA Belkin adapter and this monitor now works. For those struggling with this issue, this isn't a solution to the original problem, but it works. I bought it from the Apple Store for $32 dollars. Is it worth $32 dollars? I would say so if it gets my monitor up and running. Is it good that I needed to spend $32 to get a monitor working because of an OS update? No... but you may think otherwise.

Link to the product, which you can probably get at half the price elsewhere is below. (but I wanted Apple to own this if it didn't work so I bought it through them...)

https://www.apple.com/shop/product/HJUZ2ZM/A/belkin-usb-c-to-vga-adapter?afid=p238%7CsDb8WwLtF-dc_mtid_1870765e38482_pcrid_246387003261_pgrid_49565832687_&cid=aos-us-kwgo-pla-btb-3pp--slid---product-HJUZ2ZM/A

I had that issue a few times - no magic fix, other than uninstalling and trying again until it was there.

Hi, I have a similar issue and it's not gone after upgrading to MacOS Catalina 10.15.7.

Any other updates on the issue?

May I ask what dock are you using?

Thanks!

ASUS Zen Screen: https://www.asus.com/uk/Monitors/MB16AC/

Totally agree. Premium price must translate in perfect quality. Apple is the new North Korea. They're stuck in the feedback loop of their own myths.

Safe mode is the same result. Both screens go blank and laptop screen flutters when the external monitor is plugged in. External display shows “no connection” for 3 seconds then goes black then shows again for three seconds and goes black.

very frustrating

It has been suggested that the graphics subsystem has always had the ability to test the integrity of cables used to connect displays. It is possible we are seeing Apple more-closely enforcing the correct standards.

There are three types of HDMI cables, but they are generally impossible to tell apart once they are out of the box;

Standard --

suitable for up to 1080i and 720p NB> this is nowhere near HD, which uses twice that data rate for 1080p

High speed --

suitable for 1080p, or 4K 2 30 Hz, not faster, and deep color at those rates

Premium high speed /Ultra High Speed --

REQUIRED for anything faster than 4K at 30Hz.

.

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display.

This query is only sent at certain times:

• at startup

• at wake from sleep

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.

Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.

N.B.>>

Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own cannot respond to the Mac's query, and will stay dark.