When sharing my MacBook with my iMac I can't scale up the laptop screen to fit the desktop. It appears easily enough but only at its actual size (13" on a 27" screen). I've reset all the right parameters, such as "Scale to fit available space," but nothing seems to work. Am I missing something? I bought the iMac second hand to act as a larger screen for my MacBook.
Specs:
MacBook – 2020 M1 (macOS Tahoe 26.2)
iMac – 2011 i& (OS X El Capitan 10.11.6)
Julian Day wrote:
Am I missing something? I bought the iMac second hand to act as a larger screen for my MacBook.
How are you using it as a larger screen?
Although the 2011 iMac can act as a Thunderbolt Target Display for some other old Macs, Apple placed restrictions on Target Display Mode. Your M1 MacBook is too recent to support using any iMac as a Target Display.
See the bad news here: Use your iMac as a display with target display mode – Apple Support
As for AirPlay to Mac (a lower-quality way of using a Mac as a display), the 2011 iMac is far too old to support being an AirPlay Receiver. You might be able to AirPlay from the iMac to the MacBook Pro, but that is the reverse of how you have things set up.
See the bad news here: Continuity features and requirements for Apple devices – Apple Support
I suppose that you might be using Screen Sharing. That isn't meant to be a substitute for a real hardware monitor – more a way of letting you use one Mac to view and control the screen of another Mac on your network.
As far as resolution controls for screen sharing, see if there is anything in: Apple Support – Mac User Guide – Share the screen of another Mac
Julian Day wrote:
Am I missing something? I bought the iMac second hand to act as a larger screen for my MacBook.
How are you using it as a larger screen?
Although the 2011 iMac can act as a Thunderbolt Target Display for some other old Macs, Apple placed restrictions on Target Display Mode. Your M1 MacBook is too recent to support using any iMac as a Target Display.
See the bad news here: Use your iMac as a display with target display mode – Apple Support
As for AirPlay to Mac (a lower-quality way of using a Mac as a display), the 2011 iMac is far too old to support being an AirPlay Receiver. You might be able to AirPlay from the iMac to the MacBook Pro, but that is the reverse of how you have things set up.
See the bad news here: Continuity features and requirements for Apple devices – Apple Support
I suppose that you might be using Screen Sharing. That isn't meant to be a substitute for a real hardware monitor – more a way of letting you use one Mac to view and control the screen of another Mac on your network.
As far as resolution controls for screen sharing, see if there is anything in: Apple Support – Mac User Guide – Share the screen of another Mac
Network Screen Sharing has size and resolution limitations when it is being used with older Mac's. To put it another way, High Performance screen sharing is only available with Mac computers with Silicon chips that can run macOS Sonoma 14 or later.
IMHO, you would be much happier using an after-market display with your Mac Book Air, than the old iMac.
see Display Support, at > MacBook Air (M1, 2020) - Technical Specifications
I am using network screen sharing to connect my 2024 M4 Pro Macbook Pro. I am using a WIRED ethernet connection.
After some fiddling, I found that on my Macbook Pro, I had to go to the Macbook Pros's Settings > Display and set the resolution option to "More Space." Now I have the 14-inch Macbook Pro screen using the full 27-inches of my 2017 iMac 5k with minimal lag, at least while working these forums.
den.thed wrote:
IMHO, you would be much happier using an after-market display with your Mac Book Air, than the old iMac.
see Display Support, at > MacBook Air (M1, 2020) - Technical Specifications
and > Use an external display with your MacBook Air
I don't believe that the OP told us whether their "MacBook – 2020 M1" is a MacBook Air, or a 13" MacBook Pro with a plain M1 chip.
For completeness: MacBook Pro (13-inch, M1, 2020) - Technical Specifications
However, in terms of video support, it doesn't really matter. These two "plain M1 chip" notebooks are identical when it comes to external display support. (With Apple Silicon Macs, many features tend to be determined as much by the System on Chip as by the "chassis" it happens to be in.)
The iMac allows me to screen share, it just won't display the MacBook screen bigger than 13". Do you mean that the restrictions are not on sharing the screen but resizing it?
FYI it shares the screen remotely, without cables
So even if the MacBook screen is shared seamlessly with the iMac, it can't be sized up?
Yes that is correct.
Good point, plus the 2020 M1 Mac Book Air has a 13.3-inch display.
MacBook Air (M1, 2020) - Technical Specifications
Like you say, both offer the same external Display Support.
Can't scale up MacBook to full screen on iMac
