Users of popular Mac desktop extension app Duet Display are being advised not to update to macOS 10.13.4, due to "critical bugs" that prevent the software from communicating with connected iOS devices used as extra displays.

When installed on a Mac and an iPad (or iPhone) and the two devices are connected using a Lightning cable or 30-pin connector, Duet allows users to extend their macOS desktop space on the Retina display of the iOS device. However, unspecified changes in the latest update to macOS High Sierra, released by Apple yesterday, causes the Duet client app to hang, and users are being advised to hold back from upgrading, at least for now.

duet display
Duet's developers are recommending that users contact Apple through the company's online bug reporting form to get the issue prioritized. In the meantime, the developers are "actively looking" into workarounds to reinstate Duet's functionality in macOS 10.13.4.

Duet Display is priced at $19.99 in the App Store, and unlocking the Pro features to turn the iPad Pro into a drawing tablet costs an additional $19.99 per year through an in-app subscription. Duet Display is available from the App Store. [Direct Link]

Update: Users of other desktop extension apps like Air Display and iDisplay are also reporting incompatibility with macOS 10.13.4. DisplayLink-enabled USB graphics devices are also reportedly affected. There's some speculation that Apple's added eGPU support in 10.13.4 is the underlying cause of the issues. We'll keep readers updated if we hear more.

Related Forum: macOS Mojave

Top Rated Comments

ouimetnick Avatar
92 months ago
Is it really a bug or did Apple intentionally change things that happened to break compatibility? Might not be a bug, and just the outcome of system changes to macOS
Score: 14 Votes (Like | Disagree)
rorschach Avatar
92 months ago
It never used to be this way with Apple, but unfortunately, this is what they’ve become.
Yes it did. People have ALWAYS said this.

I remember Snow Leopard wiping out people’s entire home folders. And 10.2.8 killing Ethernet. Etc.
Score: 12 Votes (Like | Disagree)
Bryan Bowler Avatar
92 months ago
I’ve been saying this for a year now and it still holds true: if you rely on your Mac for work, you can no longer trust Apple.

I have lost all faith in Apple’s ability to release software updates that do not break critical functions. There has not been a single major dot release in the last two years that has not broken something critical to my workflow. Not a single one.

After High Sierra is stable, I will not update my Macs for nearly a year until the next OS has stabilized. It never used to be this way with Apple, but unfortunately, this is what they’ve become.
Score: 12 Votes (Like | Disagree)
thadoggfather Avatar
92 months ago
Not a bug at all; 10.13.4 only supports displays which are directly connected by a GPU or by AirPlay.
Removing the clutter

Like battery estimates.

I still modify battery.menu to output battery
Time predictions on 10.12.6 even tho they scrapped it after .1 or .2 or something

Apple can’t come up w new features so new features has to be taking away features.
Score: 10 Votes (Like | Disagree)
TheMacDaddy1 Avatar
92 months ago
I’ve been saying this for a year now and it still holds true: if you rely on your Mac for work, you can no longer trust Apple.

I have lost all faith in Apple’s ability to release software updates that do not break critical functions. There has not been a single major dot release in the last two years that has not broken something critical to my workflow. Not a single one.

After High Sierra is stable, I will not update my Macs for nearly a year until the next OS has stabilized. It never used to be this way with Apple, but unfortunately, this is what they’ve become.
Hmmm....I use one every day for work (network engineer) and I would not have it any other way.

My only real complaint is when I have to use my USB to serial adapter to console into piece of equipment on site. USB-C to USB-A dongle, Keyspan USB-A to serial dongle, null modem cable to device or serial to ethernet to device. It is quite the frankestein setup in those cases....but it works every time.

I live in Omnigraffle Pro, Safari, Terminal, Secure CRT, mail, Excel, Word, etc.
Score: 7 Votes (Like | Disagree)
KPOM Avatar
92 months ago
('https://www.macrumors.com/2018/03/30/mac-desktop-extender-duet-bug-macos-10-13-4/')


Users of popular Mac desktop extension app Duet Display ('https://www.duetdisplay.com') are being advised not to update to macOS 10.13.4, due to "critical bugs" that prevent the software from communicating with connected iOS devices used as extra displays.

When installed on a Mac and an iPad (or iPhone) and the two devices are connected using a Lightning cable or 30-pin connector, Duet allows users to extend their macOS desktop space on the Retina display of the iOS device. However, unspecified changes in the latest update to macOS High Sierra, released by Apple yesterday ('https://www.macrumors.com/2018/03/29/apple-releases-macos-high-sierra-10-13-4/'), causes the Duet client app to hang, and users are being advised to hold back from upgrading, at least for now.



The critical issue was highlighted by Duet's ex-Apple developers in a blog post ('https://help.duetdisplay.com/faq/305404-macos-10-13-4-support') on the Duet support site, quoted from below.
Duet's developers are recommending that users contact Apple through the company's online bug reporting form to get the issue prioritized. In the meantime, the developers are "actively looking" into workarounds to reinstate Duet's functionality in macOS 10.13.4.

Duet Display is priced at $19.99 in the App Store, and unlocking the Pro features to turn the iPad Pro into a drawing tablet costs an additional $19.99 per year through an in-app subscription. Duet Display ('http://appshopper.com/productivity/duet-display') is available from the App Store. [Direct Link ('https://itunes.apple.com/us/app/duet-display/id935754064?mt=8')]

Article Link: Mac Desktop Extension Software Duet Display Rendered Inoperable in macOS 10.13.4 ('https://www.macrumors.com/2018/03/30/mac-desktop-extender-duet-bug-macos-10-13-4/')
This was an issue all throughout the beta period. I let the developer know early on.
[doublepost=1522414141][/doublepost]
I’ve been saying this for a year now and it still holds true: if you rely on your Mac for work, you can no longer trust Apple.

I have lost all faith in Apple’s ability to release software updates that do not break critical functions. There has not been a single major dot release in the last two years that has not broken something critical to my workflow. Not a single one.

After High Sierra is stable, I will not update my Macs for nearly a year until the next OS has stabilized. It never used to be this way with Apple, but unfortunately, this is what they’ve become.
To be fair, Duet Display is essentially a hack. It isn’t as if Apple intended the iPad to be used as an extended display for a Mac. If they did, they’d have built it in themselves.
Score: 7 Votes (Like | Disagree)

Popular Stories

AirPods Pro 3 Mock Feature

AirPods Pro 3 Just Months Away – Here's What We Know

Friday April 18, 2025 5:16 am PDT by
Despite being more than two years old, Apple's AirPods Pro 2 still dominate the premium wireless‑earbud space, thanks to a potent mix of top‑tier audio, class‑leading noise cancellation, and Apple's habit of delivering major new features through software updates. With AirPods Pro 3 widely expected to arrive in 2025, prospective buyers now face a familiar dilemma: snap up the proven...
CarPlay Hero

Apple Releases Wireless CarPlay Fix

Wednesday April 16, 2025 11:28 am PDT by
If you have been experiencing issues with wireless CarPlay in your vehicle lately, it was likely due to a software bug that has now been fixed. Apple released iOS 18.4.1 today, and the update's release notes say it "addresses a rare issue that prevents wireless CarPlay connection in certain vehicles." If wireless CarPlay was acting up for you, updating your iPhone to iOS 18.4.1 should...
iphone 16 pro models 1

17 Reasons to Wait for the iPhone 17

Thursday April 17, 2025 4:12 am PDT by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models simultaneously, which is why we often get rumored features months ahead of launch. The iPhone 17 series is no different, and we already have a good idea of what to expect from Apple's 2025 smartphone lineup. If you skipped the iPhone...
Beyond iPhone 13 Better Triad

Apple's 20th Anniversary iPhone May Finally Go All Screen

Tuesday April 15, 2025 6:31 am PDT by
Apple is preparing a "bold" new iPhone Pro model for the iPhone's 20th anniversary in 2027, according to Bloomberg's Mark Gurman. As part of what's being described as a "major shake-up," Apple is said to be developing a design that makes more extensive use of glass – and this could point directly to the display itself. Here's the case for Apple releasing a truly all-screen iPhone with no...
maxresdefault

iPhone 17 Pro Launching Later This Year With These 12 New Features

Sunday April 13, 2025 7:52 am PDT by
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices. Subscribe to the MacRumors YouTube channel for more videos. Below, we recap key changes rumored for the iPhone 17 Pro models as of April 2025: Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and ...
iOS 19 Roundup Feature

iOS 19 Will Add These New Features to Your iPhone

Tuesday April 15, 2025 7:37 am PDT by
The first iOS 19 beta is less than two months away, and there are already a handful of new features that are expected with the update. Apple should release the first iOS 19 beta to developers immediately following the WWDC 2025 keynote, which is scheduled for Monday, June 9. Following beta testing, the update should be released to the general public in September. Below, we recap the key...
top stories 2025 04 19

Top Stories: iPhone 17 Pro Rumors, CarPlay Bug Fix, and More

Saturday April 19, 2025 6:00 am PDT by
This week saw rumor updates on the iPhone 17 Pro and next-generation Vision Pro, while a minor iOS 18.4.1 update delivered not just security fixes but also a fix for some CarPlay issues. We also looked ahead at what else is in Apple's pipeline for the rest of 2025 and even the 20th-anniversary iPhone coming in 2027, so read on below for all the details on these stories and more! iPhone 17 ...