External display not working after installing MacOs Catalina

I can't speak for markebrandon but I think the point he is making is that Apple are well aware of the issue, see my recent post, I didn't know about the issue at all, contacted Apple support through my AppleCare and they said yup we know about the issue and have no fix, I think that was what Mark was clarifying and I agree with him - I think most seasoned users on here are aware that Apple are not (understandably) present on a peer to peer user forum :)

Now I need to go spend some money on new cables as a workaround for an Apple OS issue.

I’m pretty sure my failing HDMI cables are 60hz but maybe they are not the best quality. I’ve had them for a while. They are both different makes too. The DVI cables work fine but aren’t totally flawless in that when everything is sleeping the monitors keeping popping up a “no signal” window every minute or so unless I disconnect them. But at least they work when I need them to.

2 days and $38 later the problem is NOT completely fixed. It is "better" in that the MacBook seems more adamant about connecting to the monitors; but there are sill issues between the two. It requires less reboots to wake the monitors up but there are still problems here. One thing I can say over the other two cables is it more obvious to me now that the Mac is cycling through different resolutions until it finds the one that matches the monitors but it is still struggling. Before it just seemed the monitors were gong dark and the main screen would just flicker until I disconnected the two monitors and the main screen is stagnant.

Yeah...I would suggest that folks save their money on buying new cables. I thought my purchase of these cables did the trick and I was so confident that I posted here a few threads up that I finally found the solution. But the new cables only worked for a couple of hours...maybe 6 at most. The problems started returning on the very next reboot.

https://www.amazon.com/gp/product/B075V5JK36/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

No. The laptop is more receptive after replacing the cables but the problem is still there. Every time I reboot its a crap shoot as to whether the monitors will work or not. Most of the time it requires multiple reboots.

Any solutions to this problem please ? I am facing the same issue as well. It was working perfectly fine before the installation.

Installed Catalina and external display stopped working (Lenovo ThinkVision 27" )

Connected with type-c. Tried going to system preferences-> displays-> Opt button and clicking detect displays, no effect.

Tried restarting few times, but no luck.

Any workarounds ?

I am new to this whole thing (International teacher recently relocated to teaching from home). While trying to hook my MBP to my Dell 3100 docking station to use my external monitors, I am only getting partial connection (speakers work, document camera works partially), but the monitors will not turn on. They work with my wife's HP Chromebook, but not my Mac. The docking hub connects via USB B 3.0, so I bought a converter from this to USB C on Amazon. Still no luck. I have read all 7 pages of this thread, but everything is about direct hook-up. I couldn't find anything about using a docking hub.

Any help??

Hi! I am having the SAME EXACT ISSUE. My secondary monitor is no longer being detected by my iMac. I opened System Preferences-> Displays, held down option key and clicked Detect Displays. Nothing happened.

Any ideas?

DisplayLink (formerly Newnham Research) is a semiconductor and software technology company. DisplayLink USB graphics technology is designed to connect computers and displays using USB, Ethernet, and WiFi. It also allows multiple displays to be connected to a single computer.

DisplayLink's primary customers are notebook OEMs (HP, Dell, Toshiba, Lenovo, Acer, Asus), LCD monitor manufacturers (AOC, ASUS) and PC accessory vendors (Startech.com, Targus, Belkin, Kensington, Plugable), supporting the Microsoft Windows, macOS, Android, ChromeOS and Linux operating systems.[1]

from:

https://en.wikipedia.org/wiki/DisplayLink

.

I am not happy at all that I have updated to Catalina and my external display is not working as well as no longer being able to use my Microsoft Office applications. I am using a WAVLINK dock for my externals.

WTF ! I reinstalled my Macbook pro operating system with the hope that it would fix the problem! It turns out, not only it didn't solved anything, but also the external monitor doesn't detect the laptop at all! At least, before that, it worked after a couple of times restarting. I use usbc to DVI. The monitor doesn't have any HDMI port, so Displaylink solution doesn't work for me.

How do you manage to connect your monitor? Do you also restart your laptop multiple times and wait half an hour?

I posted four ways to get your Mac to send the query to "see" and use an external display above.

Any one of those four can be used to induce the Mac to send a query, and hopefully your display would respond with its name and capabilities.

I have gone through every single trouble-shooting step with no luck. What is most annoying is that the cables clearly work - my monitor is still powering my MacBook, but the monitor stopped working the day I "upgraded" to Catalina. I tried downgrading back to Mojave, and the monitor would no longer work. I am connecting USB-C to USB-C with cables from the Apple store. Is it possible these no longer work? This is incredibly frustrating.

The Apple charge cable has ONLY power pathways in it. the only data is USB-2,suitable for keyboards. there are no high speed data pathways whatsoever.

Although it may seem like you have entered the Twilight Zone, the new reality in the age of USB-C connectors is:

1) USB-C is the name of the connector, ONLY and

2) the connector tells you NOTHING about what any cable is capable of doing for you.

I have a slightly different problem. i had issues in the past with my thinkvision P24h-10 display not being a full size, in the previous macOS upgrade the problem is fixed, with the new upgrade to Catalina 10.15.5 the problem appeared again and i lost 2 inches on all four sides of the display. anyone else with this problem?