Catalina gets resolution wrong when HDMI switching external monitor

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Level 1

75 points

Catalina gets resolution wrong when HDMI switching external monitor

I've been using my MAC with a HDMI splitter to share a 4K monitor for a number of years. I've ever had a issue until the last 2 supplementary release of 10.14.6 Mojave where it seems resolution and control of the monitors got all mixed up (see my previous posts). The fix to Mojave night shift resulting in high cpu (as the kernel tried to change resolution every 1ms) was to upgrade to Caalina or turn off night shift. Indeed Catalina did fix the kernel issue however now with Catalina I have a separate issue. Normally the 4k monitor runs at 60hz and 3840x2160. However, with Catalina, if I switch the monitor between the MAC and windows and then back to MAC when reconnecting to the MAC it selects 30Hz and a resolution that is much lower than before switching and large fonts. The only way to get the resolution back is to completely disconnect the MAC, wait 30 seconds, and then plug it back in. Kind of defeats the purpose of HDMI switching but.... This particular issue did not happen with Mojave or High Sierra so it appears Catalina specific. Anyone aware of any settings that could address this behaviour?

MacBook Pro 13", macOS 10.15

Posted on Dec 1, 2019 11:24 AM

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Answer 1

nullcode

Level 1

13 points

Dec 2, 2019 7:32 AM in response to BradSP

I have a similar issue with Catalina. I have a 2018 Macbook pro, with a Samsung 55" QLED TV as my main display via HDMI (USBC->HDMI) and it works beautifully on Mojave, however on Catalina the "Default" resolution on my monitor is now 1920x1080, and not 3840x2160 as it is on Mojave. Going into display settings, I can change this manually, and does use 60 Hz, so I was content.

That was until I found that whenever my laptop went to sleep, or even just turned the display off - on wake, it would be back to 3840x2160, however all windows would be stuffed into a 1920x1080 square in the lower left of the screen - making it unusable. After a few days of fighting with this, and apple confirming the issue, I went back to Mojave. I do hope this issue is fixed soon.

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Answer 2

BradSP Author

Level 1

75 points

Dec 12, 2019 12:23 PM in response to BradSP

Well seems that 10.15.2 is out but by the initial feedback I'm thinking I may well avoid it completely give the fact that I use a external Apple 27in monitor and looks like the initial feedback is that these are now not working. There is more than 1 thread on this in mac rumors. This means I will put off playing with the MAC until the weekend because its going to need lots of stuffing around and time to determine if I am inflicted by the same issues as others and rolling back etc Appears to be a continuation of external monitor issues. Wonder if at some point Apple may get it right?

https://forums.macrumors.com/threads/external-display-not-working-since-upgrading-to-10-15-2.2215286/

Also monitors working on .1 that no longer work after .2 upgrade...

https://forums.macrumors.com/threads/external-display-not-working-since-upgrading-to-10-15-2.2215286/?post=28058184#post-28058184

Looking at the release notes there is nothing in there that I need in my daily work life other than maybe the security updates. Unfortunately they will take a back seat to workflow still being functional afterall that is what pays my bills. Anyway, weekend job to back up, test, and rollback potentially. Managing my MAC upgrades has become a hassle much worse than windows in the last 12 months.

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Answer 3

nullcode

Level 1

13 points

Jan 30, 2020 12:04 PM in response to BradSP

I upgraded without issues, however it did not help my HDMI issues. I still only get 30 Hz when not in Mirror mode, and waking from sleep often does not show anything on the monitor - need to replug the USB-C to HDMI adapter to have it come back up. I am worried it will break the port on my device if I have to keep doing this.

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Answer 4

Tesserax

Level 10

157,854 points

Dec 1, 2019 11:55 AM in response to BradSP

To help understand your current setup, may I ask a few questions?

Which exact model is your MacBook Pro
... and 4K monitor? What video ports does it have?
Is your notebook now running macOS Catalina 10.15.1?
How about your Windows PC? Is it running Windows 10?
Does it have a dedicated graphics card or use built-in graphics? Regardless, in addition to HDMI, does it sport any other video connections ... like Mini DisplayPort?
What is the make & model of the HDMI splitter that you are using?

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Answer 5

BradSP Author

Level 1

75 points

Dec 2, 2019 11:53 AM in response to Tesserax

Thanks @Tesseax. I run this way because I'm too lazy to switch the monitor manually and I like the remote control of the HDMI switcher. Pity that Apple just seem to have continued backwards on external monitors since 10.14.5. My daughters MAC (on 10.14.5) shows none of these issues. Unfortunately trying to go back to Mojave yields a 10.14.6 version which has similar and worse bugs than Catalina so far. I guess I am stranded until Apple fix these issues. Thanks for the suggestion.

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Answer 6

BradSP Author

Level 1

75 points

Dec 13, 2019 2:16 AM in response to BradSP

Well had an absolute awful time upgrading to 10.15.2. Took 3 times with each rolling back to a working .1 to try again. Seems that during the upgrade process the WindowServer process dies and stops everything from progressing.

I can confirm this problem still exists in 10.15.2.

Time to roll back to avoid any other 10.15.2 issues i could inherit that I don;t want. Wasted 3.5 hrs the way it is to get an actual upgrade to work....

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Answer 7

BradSP Author

Level 1

75 points

Dec 13, 2019 2:16 AM in response to BradSP

Well had an absolute awful time upgrading to 10.15.2. Took 3 times with each rolling back to a working .1 to try again. Seems that during the upgrade process the WindowServer process dies and stops everything from progressing.

I can confirm this problem still exists in 10.15.2.

Time to roll back to avoid any other 10.15.2 issues i could inherit that I don't want. Wasted 3.5 hrs the way it is to get an actual upgrade to work....

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Answer 8

BradSP Author

Level 1

75 points

Dec 14, 2019 3:16 PM in response to BradSP

Well 10.15.2 kernel dumped twice overnight. Thats it rolling back to 10.15.1 as at least it did not exhibit this behaviour. Quality of these updates is getting worse in each release. Really is time to find a stable release and stick to it.

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Answer 9

BradSP Author

Level 1

75 points

Dec 14, 2019 9:18 PM in response to nullcode

If going from Catalina back to Mojave you will get a weekly error report about potentially being hacked or some thing like that. There is a weekly validation of the firmware checksum against the release. Since Catalina updated the firmware it will not match Mojave....doesn't stop anything that I am aware of however...just another pain.

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Answer 10

BradSP Author

Level 1

75 points

Dec 14, 2019 9:21 PM in response to BradSP

I've returned to 10.15.1. I can just manage to put up with HDMI issues but simply not the kernel crashes. At least 10.15.1 never did that to me. Guess will wait probably until the second last release of Catalina to update...that was the most stable of Mojave.

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Answer 11

nullcode

Level 1

13 points

Dec 14, 2019 9:39 PM in response to BradSP

I went to Catalina when it was first launched, and reverted back to Mojave a couple days later after all the issues it caused. Have been happy since, and do not get any weekly error reports, etc.. In fact the only annoying thing I get is the continual "update" that is available to install Catalina. I was able to hide the update, so that is not so bad either.

Happy to sit and wait until Catalina is more mature.

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Answer 12

BradSP Author

Level 1

75 points

Feb 1, 2020 10:52 AM in response to nullcode

Thanks @nullcode for the response I hope you do not inherit other issues. I've learn now from my past history here with Apple that once you get some thing that works stop upgrading. By the looks of it, if the external monior issues get resolve it will be almost a year after they got broken as such. Thats one slow pace to fix bugs. I'm staying on 10.15.1 for now. Thanks again for the feedback, disappointing but what was expected.

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