Touch bar bug: Up to macOS 12.5, an icon ensures network restrictions

Touch bar bug: Up to macOS 12.5, an icon ensures network restrictions

A developer has discovered an extremely strange bug that can lead to Apple users losing their Mac’s network connection – or being able to use it only to a very limited extent. The problem only affects machines that have installed the OLED function key bar Touch Bar, which Apple has since discontinued.

As the Swedish developer Martin Persson reports in his blog, after upgrading his 2019 MacBook Pro to macOS 12 aka Monterey, he was no longer able to use the Parsec remote desktop solution properly. The connection broke every few seconds, there was a constant audio lag and “rubber banding”. Persson initially suspected that Parsec simply did not support Monterey adequately, but he found no information on the subject in support forums.

After further troubleshooting attempts, it turned out that other streaming services such as Steam Play were also affected, and the entire Internet connection on the Mac was only half as fast, although an iPhone speed test in the same network showed that everything was fine. Further investigations showed that there were “rhythmic waves and spikes” in the ping behavior via WLAN. The problem was also reproduced in other networks, but confusingly not in a freshly created user account on the MacBook Pro.

After a long search, Persson finally realized that it was apparently a bug related to Apple’s local streaming protocol AirPlay – because it only occurred when you were in networks with the appropriate devices (Apple TV). More specifically, a process called “AirPlay (DFRExtra)” was the culprit. And the “DFR” here stands for “Device Function Row”, an Apple name for the Touch Bar. Lo and behold: Persson had configured an AirPlay button in it. Apparently, the process runs amok as soon as AirPlay devices are connected to the network. If the button is removed, however, the network performance runs as usual.

So Persson submitted a bug via Apple’s Feedback Assistant. He was able to reproduce the problem in all macOS Monterey versions from 12.0 to 12.4. And there was a happy ending: A few months later, Apple actually responded. The developer received a response to his feedback filing and the bug fix appeared in macOS 12.5 – albeit without comment and without mentioning it in Apple’s package insert. The “AirPlay (DFRExtra)” process has been modified in such a way that it appears to only be looking for AirPlay devices when it has actually been activated – and not all the time. If it is deactivated, the search also stops. macOS 13 aka Ventura, where the bug was also present, fixes it in Beta 3.

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