All posts tagged macos

One of the most puzzling things about the Apple Silicon MacBook Air in 2024 is that it can only natively support one external display. This even extended to the early 13″ MacBook Pro, which was just an Air with a Touch Bar. I’ve supported many of these devices since their introduction, M1 and M2 chips, 13″ and 15″ sizes. As of this post, there’s only one way to get full support for multiple displays.

Synaptics has a technology called DisplayLink, which they license to many companies from StarTech, Hyperdrive, Pluggable, and more. Download the drivers from their website and it tricks the OS into sharing a virtual display with the adapter, letting a user have multiple displays. It works quite well, but has it’s limitations. One of these popped up recently when upgrading from macOS Ventura (13) to Sonoma (14) and using the Zoom accessibility feature. It’s something that I use often in order to make text easier to read, and is pretty important, so when the display connected to my StarTech DisplayLink adapter stopped zooming I was a little puzzled. But I wasn’t surprised, because Apple has been tinkering and changing things for years and breaking capabilities like this.

In an accidental way I was able to find a solution, however, because it is possible to not only support Zoom on both displays, but unlike in Ventura, each display seems to magnify independently. This is a change from Ventura, where the combined display width and height were treated as a single display. Zooming in on one display or the other would also zoom the other, which wasn’t ideal, but worked.

In switching from a Hyperdrive dock to an older, first-generation 13-port OWC Thunderbolt 3 dock, I was unsure which display was connected to which cable, This dock is very odd in that it’s only display outputs are Thunderbolt 3/USB-C DisplayPort and a miniDP plug. No HDMI or full DP plugs. I was using a miniDP-to-DP cable on Dell displays, but found out that I needed to move it. In this confusion I found that the DisplayLink adapter had grabbed the top bar, making it the primary display. This isn’t the monitor that I would normally use as primary, so I was going to change it but found myself using the zoom motion to make the System Preferences panel larger and had to pause and think about what just happened.

After the Sonoma update, this adapter being set to the secondary display, it no longer zoomed. Instead, it glitched a little bit and stuttered. That it was working was unexpected, and so I checked to see if somehow the issue had been resolved by setting things back up as I had previously. Primary was from the dock, while secondary was from the StarTech adapter. The issue returned. So, I switched it back and the zoom worked as expected and hoped. I thought about using my second display as the primary monitor, and even set it up like that for a few minutes, but thought about the whole situation again.

Why was the DisplayLink adapter working when it was primary? I don’t know, but there must be some kind of priority and feature enabled when it is. Thinking for a moment I then decided that switching the two display inputs couldn’t hurt, so that’s what I did. It worked exactly has I’d hoped, and is very much a solution to the problem I’d has since upgrading to Sonoma.

As mentioned earlier, I can now zoom in on either monitor independently of the other. In this window I’m zoomed in, while the other is zoomed out to the full, native resolution. There’s no choppiness or lag, which I did admittedly remember happening on the DisplayLink adapter under Ventura. This behavior is why I wouldn’t have considered the StarTech USB adapter fit for the primary display. Now, however, it works easily as well as the display connected to the dock.

I had emailed Synaptics earlier to ask if this was a known issue and received a response that it was. The software as of this writing is 1.10.0 Build 117 and was released in October 2023. No beta is available. I have emailed that same contact to inform them that there is a possible resolution for some users and I hope that they will acknowledge this and that it’s already a known fix.