Unable to change resolution on extended display / external monitor

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4 points

Unable to change resolution on extended display / external monitor

Hi, I've been using a Toshiba monitor as an extended display for my 13inch MacBook Pro M1 for over three years. After the last Ventura upgrade, something seems to have gone wrong with the resolution.

The monitor view is now blurry and everything on it is enlarged to the point of being virtually unreadable. I have tried adjusting the resolution of the extended display in the System Settings (as per instructions on Apple's site), but this doesn't seem to be working as it should. It's now only offering me two resolution options for this display (800x600 default or 1280 x 1024). When I try to click 1280x1024, it immediately jumps back to 800x600.

I've tried unplugging, turning off and on and reconnecting, but nada. I've also scoured Google for other recent reports of this issue and haven't been able to find any suggestions to fix it. I did also log an error on the Mac issue site last week, but haven't seen any updates about this.

It's getting frustrating and not sure if I'm going to have to replace the monitor, which seems like an excessive fix. This monitor can also be used as a smart TV and all the display viewing options for that are still working correctly with no resolution issues, so it seems to be coming from the Mac.

Any ideas? Thanks

MacBook Pro 13″, macOS 13.3

Posted on Apr 29, 2023 4:54 AM

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Answer 1

Best reply

ITSP2023

Level 1

18 points

May 2, 2023 9:03 AM in response to MBond22

The same problem. I used Display Menu - 3rd party software that works. But you have to change resolution on every startup...

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Answer 2

MBond22 Author

Level 1

4 points

Apr 29, 2023 4:57 AM in response to MBond22

Just some further info on this. When I click "show further resolutions" for this monitor in System Settings, it offers a host of options, but it won't allow me to change the resolution to any of them.

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Answer 3

Apr 29, 2023 7:59 AM in response to MBond22

as you found, Analog VGA tops out earlier than digital connection methods.

If you still have issues, HDMI cables come in a variety of capabilities, and it is not clear what an unmarked HDMI cable can accomplish.

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

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Answer 4

Apr 29, 2023 7:20 AM in response to MBond22

If you have accidentally (or on purpose) selected [√] Mirror displays, the two displays are both set to a 'compromise' resolution that both appear able to attain, and run from one display-generator, in perfect sync.

after unchecking the box or dragging the two displays apart, your displays should show as a proper "Extended Desktop":

.

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Answer 5

MBond22 Author

Level 1

4 points

Apr 29, 2023 7:35 AM in response to Grant Bennet-Alder

Hi Grant, thanks for your suggestion. The external display has been set as extended, not mirrored, but to test I followed your instructions, changed it to mirrored and then changed it back again. Unfortunately it's not making any difference.

Attached screenshot, showing my options for the extended display. However, irrespective of which of these screen resolution options I try to select, it makes no difference to the view or resolution. It only shows the default view of 800x600. It won't allow me to change it. It's the strangest thing.

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Answer 6

Apr 29, 2023 7:40 AM in response to MBond22

what make&model display, or a link to its specs?

EXACTLY what cables, adapters and docks are in use? please mention every item.

what model-year MacBook Pro, and if around 2020-ish, what processor?

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Answer 7

MBond22 Author

Level 1

4 points

Apr 29, 2023 7:53 AM in response to Grant Bennet-Alder

Mac: Macbook Pro 13inch 2020, M1.

Monitor: Toshiba https://toshiba-tv.com/uk-uk/full-hd-tv/24WL3A63DB

Cables: VGA cable and Apple VGA adaptor.

UPDATE: Your question made me realise I needed to check the adaptor and cable. I've just plugged in an HDMI and that seems to be the issue!

It's allowing me to change the resolution to a few different options, way better than what I've been dealing with.

So, resolved. Thanks for your question, it helped get to the bottom of this. It appears VGA isn't the best option anymore. :)

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Answer 8

MBond22 Author

Level 1

4 points

Apr 29, 2023 8:06 AM in response to Grant Bennet-Alder

Appreciate the further advice Grant. This cable does happen to be a "High Speed HDMI with Ethernet" - it's a long one though which I use for presentations. I'll be sure to order a shorter version with the same specs. Thank you.

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Answer 9

MBond22 Author

Level 1

4 points

Apr 29, 2024 12:39 PM in response to LeemsWithDaBeens

@LeemsWithDaBeens I used a High Speed HDMI with Ethernet capability. Previously I had been using a VGA cable which suddenly became incompatible. The advice was given by @GrantBennet-Alder in a post above, he recommended the following:

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet" --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

Reply