Hi!
If I connect a 4K monitor (TV) to Mac mini (M1) and access Mac mini via Screen Sharing from iMac 5K Retina, then I get nice, high resolution screen of Mac mini on iMac 5K. If I detach the 4K TV from Mac mini (M1) the Screen Sharing resolution deteriorates to 1920x1080 on iMac 5K and no way get high(er) resolution. Screen Sharing Preferences does not help. Any idea, how to get high (4K) resolution via Screen Sharing if no HDMI attached to Mac mini (M1)?
Hi gyesi,
We appreciate the reply, and thanks for testing that in a new user account.
What happens if you click "Default for display" instead of "Scaled?" Does that make a difference?
Also, to clarify, are you physically disconnecting the HDMI cable while screen sharing is active?
Have you tried a reset of your NVRAM? If not, give that a try; that can help with many display and resolution issues: Reset NVRAM or PRAM on your Mac
Cheers.
Hi gyesi,
Thank you for using the Apple Support Communities. It looks like you're using screen sharing between a Mac mini and iMac 5K Retina and have a question about the resolution. We'd like to learn more about what's happening to see if we can assist.
For clarification, are you saying that if you disconnect the external display for the Mac mini while screen sharing, the resolution changes on the iMac and you're then unable to change it?
To narrow this type of behavior down, it's a good start to test it in a newly created administrator account. That will help rule out potential user-specific causes, and can help work out whether it's system-wide or possibly expected. Here's how to Set up users, guests, and groups on Mac. Once you've created the admin account, sign in there and test it out, and let us know how it goes.
Best wishes.
Hello gyesi,
We appreciate the clarification! To look into this one further, we recommend getting in touch with Apple directly using this link: Contact Apple Support
Best wishes.
Hi ryanne77,
Thanks for your reply. Correct, if 4K TV is disconnected from Mac mini, the resolution on iMac goes from 4K to 2K.
While 4K TV connected System Preferences -> Displays -> Display -> Resolution -> Scaled: the four options (Larger Text --- More Space) are available.
When HDMI pulled out from Mac mini the resolution deteriorates immediately and visibly. "Scaled" option: 1920 x 1080 - only.
Creating new admin account didn't help, unfortunately.
Bye, gyesi
Hi ryanne77,
"Default for display" is exactly the same as "Scaled", i.e. 2K.
Yes, I pull out the HDMI cable from Mac mini while screen sharing is active - and resolution goes from 4K to 2K
I have not tried the reset of NVRAM, the link you sent applies to Mac with Intel CPU. My Mac mini (M1) is with Apple Silicon and I found about : "NVRAM is available in the M1 Apple Silicon Chip, but the machine is configured to automatically run test on startup and automatically reset the NVRAM if needed. There is no option to trigger it manually!"
Did you have a chance to test whether limitation to 2K (if not connected to 4K display) is a general "feature" or just happens with my Mac mini (M1)?
Bye
Hey there gyesi,
Thanks for replying back! There might still be a few things you can try to narrow this down since the NVRAM reset is not possible on your Mac model. To double-check, if you end the screen sharing session without disconnecting the cable, what happens to the resolution on your iMac 5K Retina? Knowing those results should help in getting to the bottom of this. You can turn it off under System Preferences > Sharing.
Keep us posted, and have a good one.
Hi ryanne77,
Maybe I was not clear, but iMac's resolution is always 5K - before/during/after screen sharing session - regardless of connected Mac mini's resolution.
My concern is about the Mac mini's shared screen appearance on iMac. Unless a 4K TV/display is connected to Mac mini, the shared screen (that particular window only) resolution is only 2K, the "rest" of iMac is 5K. And as I use Mac mini as headless server, no intention to attach any display to it.
As clarification, the two screenshots I sent earlier, are Mac mini's System Preferences appearing on iMac.
The screenshot below shows two System Preferences.
Left: iMac's own (5K).
Right: Mac mini's shared screen - when no (4K) display connected to it - on iMac. 2K only.
Is any way to "force out" a 4K/5K screen sharing from a headless Mac mini (M1)?
Bye, gyesi
Mac mini (M1) screen sharing 4K
