After update from 10.15.3 to 10.15.4 external displays doesn't work via docking station

I have quality Dell monitors and a Dell docking hub that worked fine for months and were working mere minutes before the software update. As soon as the update installed, no more external displays. This is 100% the fault of the software. I realize bugs happen, and that's just part of life, but customers still have the right to be upset when they do. If they don't get upset they never get fixed. If Apple didn't want to support aftermarket products in use with their products, they would only use proprietary connectors instead of industry standard connectors like USB-C.

[Edited by Moderator]

I'm with you on this. I've seen people on here with the same problem that I'm having, and they're using equipment that is worth a lot more than mine (hubs/docks/monitors/etc.). I reiterate that my entire studio, display and all, was working perfectly UNTIL I updated to 10.15.4. (Also, yesterday's supplemental update did absolutely nothing for my situation). It's not at all an issue of having bought anything "because it is the cheapest on Ebay or Amazon." Everything I'm using I purchased at Microcenter in person. And AGAIN I'll say, no matter how "cheap" it was, IT WORKED PERFECTLY until this update.

Apple just released a supplemental update for 10.15.4, to include “resolves issues where a usb-c port in your Mac may become unresponsive”. Just wondering if anyone had tried this. My dock is working okay when I reverse the two usb-c ports, it looks very strange but at least working okay for the past few days. Kind of hesitate to try any new update......don’t want any surprise

I tried the update, but no luck. I reset all the things that I've been encouraged to reset (NVRAM/PRAM/Safemode/etc.) since the supplemental update, and still nothing. And when you say you reverse the two ports, which two? Thanks!

My mbp2019 has two usb-c ports(female), the docking device I have has two usb-c (male). Just turn it around and connect temporary solve my issue. Insertion in the proper way doesn’t power the docking so none of the ports was functional

So that small update did not fix anything for me, but I decided to take in my USB-C small ANKER adapter which has a few USB ports and ethernet port, and I connected my D6000 dock to the USB instead of USB-C, and it all works! I hope they release an update soon because I'd rather not use a dock to connect to another dock... but it works for the meantime.

Someone should reach out to Apple and your dock manufacturer and ask to escalate this to a level at which this can be solved.

And you'll might consider listing your hub/dock info so you can see which hubs are having problems (and thus assume which ones are not?).

Here is an analogy that I hope makes sense:

Imagine there were universal standards that were specific, dictating car wheels had to eventually be 6-7 feet wide, no narrower and no wider, but at first, to accommodate the widest range of possible vehicles, Apple built roads that could accommodate 5-9 foot wide vehicles. Eventually, to make road building more efficient and to accommodate more vehicles in a given space, they eventually moved to adopting the standards. They told every car manufacturer in advance so they could upgrade their vehicles to meet the universal standards, but not everyone listened, especially the cheaper lower volume manufacturers. In fact some of them didn't care because they either weren't selling enough to care, they were just reselling someone else's model, or they figured they'd sell new models if they didn't upgrade the old ones, especially if everyone blamed Apple. Who is to blame? Apple for eventually adopting the standards and telling everyone in advance, or the manufacturers who never bothered to test and upgrade their cars? Is Apple to blame because they upgraded to the new standards and now some cars don't fit anymore?

I'm not saying this is what happened, I'm just saying you can't always blame the maker of last thing you did. Cause and effect just isn't that simple.

How about a a brand new Apple USB-C to Digital AV adapter, from a 2019 Mini to Acer top end, new monitor? I also have a "cheap" new test monitor that I'm having issues with also. It all started immediately following the update. I've used the products in work and play since they actually were Apple computers. They'v had lots of hits but plenty of misses as well. People are uptight enough already.

My solution , after putting on a mask and buying a $79 apple adapter and having it finally work after much "fiddling around" only to go in to sleep mode and not come back until the 5th reboot, unplug, replug routine; I'm leaving my monitor on and awake until the fix the bug. The whole ordeal cost me at least 8 hours of wasted efforts.

Some of you probably don't even know who Michael Dell is, never mind the words he would eventually regret; Back in 1997, Dell famously said that if he were put in charge of Apple, "I'd shut it down and give the money back to the shareholders."

Regardless, I'm sorry if you bought a Dell product and expected it to play well with an Apple product. I'd start trouble shooting with Dell.

The last update didn't solve any problems. My BenQ EX3203R monitor is no longer supports 144 Hz mode. The second problem - the monitor stopped detecting the signal from the MacBook (I have to disconnect the cable, turn it on at the right moment while the monitor is "looking for" a signal).

There were no such problems before. I'm still surprised that Apple is making such critical mistakes.

This issue is not exclusive to users using docking stations or hubs. I have a DisplayPort monitor connected with a USB-C to DisplayPort cable: in 10.15.3 it works, in 10.15.4 it does not.

Trying to deny this issue is caused by the software update, or trying to incorrectly suggest Apple never ships bugs frankly isn’t helpful. I’ve personally filed radars for bugs in beta versions in macOS that have still been shipped in the final version. Apple’s feedback tools for developers are poor.

If Apple’s standards have changed as you suggest without evidence, it would be incumbent on Apple to publish those changes.

Judging from 10.15.4’s release notes, the release included changes to support for HDR displays over DisplayPort and HDMI. The most reasonable explanation is that these changes resulted in bugs that have negatively affected users of some external displays.

I have the same issue since updating 10.15.3 and hoping 10.15.4 can fix it.

I am using Ugreen USB C hub, and the monitor suddenly does not receive the signal from the hub.

I checked the ports of all USB C hub , unplugging all the connection, leaving only HDMI port.

I troubleshoot my hdmi cable with my usbC hub with my Samsung Note 10, and it works suprisingly.

but, when I used my friend's usb C hub and connect with my macbook, it still doesn't work.

idk if this is not because of Catalina 10.15.13 or else,

those "loose connections, damaged hardware" is not the options. I had troubleshoot every possible ways.

hope Apple can fix this if it is truly due to the thunderbolt connection.

(using macbook pro 13 inch 2017)

I am not saying it is or it isn’t and I’m not saying Apple doesn’t ship bugs. I’m just saying that to simply decide it is because a relatively small group of people are having a problem is not a wise pursuit.

Do you know that Apple did not pre-announce changes? Do you know that every developer tested and corrected before Catalina 10.15.4 shipped? It is nearly impossible to test every combination of cables, hubs, docks, dingles, etc.,

On almost all, if not all OS updateS, many people experience problems of one sort or another. Having done Mac tech support for a living, most problems are beyond the control of Apple. If you saw my earlier post about my audio interface, you’ll note that the developer indicated testing for compatibility.

As noted, the vast majority are not seeing the issues seen here. If they were, it would be all over the news.

All that said, the process for identifying and fixing a problem involves working with all the parts and trying alternatives. If an alternative part works fine, what’s the conclusion? That Apple software targeted the part that doesn’t work? If a bunch of people started to complain about App A not working after an OS upgrade but the vast majority didn’t have any problem, do you think the problem lies with the upgrade, because that was the last change? I don’t think that makes any sense.

I’m telling you sometimes an OS upgrade reveals different problems. Sometimes they may be an Apple bug or simply a change that results in a new problem. It doesn’t really matter but if most folks aren’t having the problem, it is wise to look elsewhere too.

I can tell you this; every update reveals a bigger problem: people don’t backup. Nearly everyone here did not back up before installing the update, even though they were warned to do so. That is indeed a problem, and it is a user problem. Looking for scapegoats isn’t going to solve that.

And just because you report something before and after beta, doesn’t mean it’s actually an Apple bug. It’s better to see it merely as a problem looking for a solution. And the pool with the problem might be quite small.

All I’m trying to suggest is to be creative in understanding the problem instead of blaming the last introduced variable.

After installing the 10.15.4 supplemental update from 8th of April my USB-C dock and attached screens work as before. Don't know if Apple made an update or if it's because of a system reset due to the update. Point is that it's now back to normal

You might check in with support at Anker. Looking at there specs it appears that some issues on this thread might be related to overloading demands on hubs/docks. Regardless here is the link at Anker: https://www.anker.com/products/variant/5in1-usb-c-adapter-with-4k-usb-c-to-hdmi/A83310A1