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

Something interesting happened. A few days ago, I needed to let the computer go to sleep first. And when it woke up, the external monitor was active, just as user gvfx2000 suggested.

But recently, I do not need to make the computer sleep any more. The external monitor works just fine every time I connect it to my Macbook Pro via usbc-displayport cable. I haven't done any additional system update since 10.15.4 (19E287) April 8, 2020 update.

I am happy things are back to normal now even though it is still a mystery why it didn't work before.

That's really strange. My Mac never got the display back again, with or without sleep. But today I turned it on in the morning and it took like 30 minutes to boot. No Application would work, not even Chrome, Safari, not to mention Creative Cloud. Rebooted a few times and the problems persisted. Called support, they could not get access to my computer because the internet was faulty on this machine. We tried a lot of things, nothing worked. I concluded I needed to do a time machine backup and reinstall the MacOS hoping this could also fix the display issue. At the end of the day, while waiting for the time machine finish the backup, the computer started working again like nothing happened.

I have a support case with a senior applecare advisor open since May 2. Got a response yesterday...

"I have a request from the same engineer I spoke with last time. I haven't heard anything yet but I’ll reach out again tonight."

No fix, no idea. I would say just wait to upgrade since 10.15.5 also does a Bridge OS firmware update that might break something else specifically to you.

It's a shame that Apple behaves like this with a non-upgradable machine that costs a ton of money. And the problem will get even worse because most of the Professional users and Enterprises in the sound industry did not update to Catalina yet since for Instance Pro Tools it's not 100% compatible yet. As soon as they do a large number of unhappy customer should arise.

Anyway, I am thinking about downgrading to Mojave because I can't work this way. I can get it to show up on App Store, but it won't allow me to download it, (Nice done Apple, it's getting better every day) so probably I will have to download it from another machine and do a clean install from an external HD, although I will. have to connect the HD to the docking station, so fingers crossed...

My question is: Anyone done that? I recall watching some users complaining that when downgrading to Mojave, the external display connection would still be broken although it wasn't before upgrading to Catalina.

Thanks.

Joaofromevora,

Do not waste your time with this. Downgrading will NOT help, this is because your video graphics card has been flashed to a newer version also. Downgrading MacOs will not re-flash your video card to an earlier version.

Hi joãofromevora,

The only way works for me right now is the method provided by gvfx2000. Does that work for you?

Normally I would first set "Turn display off after" 1min in Energy Saver of Syestem Preferences. Then connect the external monitor and wait over 1min until the macbook internal display is off. Then wake up the computer and the external display would work perfectly.

Then, I will set the "Turn display off after" to "Never" or a very long time, because if the display turns off and on again, sometimes the computer would restart for no reason and you will lose all unsaved data.

Also, once for a while, the external monitor would just work without going through the above procedure. But this is not stable. After some time, I need to go through the procedure again.

Hope this helps.

Hey smoothitaway, thank you so much for your reply; unfortunately, this doesn't work for me, I've tried a bunch of different scenarios and timings with what you said, and none of them worked. My display is off since the end of March and I leave it connected all the time hoping it magically turns on, but it never came to life once... completely out of options now. :(

Hi snaplatte, thank you for your reply.

It doesn't work.

I tried DisplayLink before with the same results; I guess my dock is not supported, they don't list it under their website.

My dock is this one: Lindy USB 3.1 Type C Notebook Docking Station. Bought it February and now when checking their website, I see it is a discontinued product. :/

Guess I'm doomed :/

Does OS X recognize a monitor was connected?

For me sometimes I have to plug the DisplayPort cable to the MacBook Pro in and out a few times and try different ports for the computer to first recognize and acknowledge the monitor, and sometimes its random which port work and which ones don't.

Hope that helps...

I have only gotten this issue when updating to 10.15.5, it not longer recognizes my Samsung 34 inch ultra wide via my 2 different USBC hubs which worked perfect before the update. I then went back to 10.15.4 but that did not work, so I am wondering if going back to 10.15.3 would work?

Hi All,

I ended up reverting to a time machine backup with v. 10.15.1 and now it's working as it was.

I spoke to Apple support for hours with no luck who then created a ticket for their engineering team. By the time they called back 24hrs later to try some more things I had reverted back as i need this for work. He also mentioned that "they have not had many reports about this, so they need to troubleshoot"... Seems faily well known on the forums, but if you have the time and no backup it might be worth contacting them.

Note: I also spoke to Alogic who basically said it was on Apple's side, however, mentioned that updating the DisplayLink drivers was a workaround for some of their products (not mine as it doesn't require any drivers). Hope this is able to shed some light for someone.

Following the 10.15.4 update my 2007 Viewsonic external monitors (connected via mini-displayport to DVI) began blacking out after waking my 2013 27" iMac from a 1+ hour sleep. Putting the system to sleep again and waking immediately usually fixed the issue, but was unacceptably annoying. All corrective measures offered in this and other discussions were unsuccessful, and the most recent update (10.15.5) did not resolve the issue. A 2019 LG monitor from another setup was tested (via mini-dsiplaypot to HDMI) and did not black out after waking from 1+ hour sleep periods, so I suspect that macOS Catalina stopped supporting (or altered timing of) an older type of video handshake (or perhaps there's an issue with DVI support).

I ended up buying new Acer monitors that are connected via mini-displayport to HDMI - problem solved - no more black outs after waking from sleep. Therefore, if others are still experiencing external monitor blackout issues I recommend testing a newer monitor. If successful then the older monitor(s) should be replaced as it's unlikely at this point that Apple will fix the problem for older monitors.

The issues are hard to figure. I'm having the same issue with new monitors, one am Acer. The big "fix" for me involved connecting to my Sony 4k, which connected immediately, powering down everything, reconnecting my monitor, power back up, and it connected.

Using Catalina 10.15.5 MBP 16" 2019 D6000 Dock. Updated the firmware with windows computer. MBP recognizes my keyboard, speakers, the dock, but not the HDMI display I have plugged in. I manually allowed DisplayLink to record screen and used the terminal to load the DisplayLinkDriver.kext. Multiple restarts, multiple reinstalls. Please help.

CalDigit Thunderbolt 3 Mini Dock for connecting 2 External Monitors for Mac Book Pro

Extending Displays was not working when I was docking my new Mac Book Pro 2020 on Catalina 10.15.5. I was using one USB C for power and one USB C for an adapter. With two external displays (not using the Mac Book's display) it was only mirroring the displays and did not recognize two external displays. The adapter was made by Monodeals. I bought the CalDigit Thunderbolt 3 Mini Dock. Yes, way more expensive - but it works correctly now.

Like many of the others that called support - they seemed to be unaware of this issue. Thanks for posting about the CalDigit adapter.