Availability macOS Big Sur was accompanied by app launch problems

Apple released macOS Big Sur on Thursday night, but the release caused server problems at the company. As a result, users were unable to launch apps or were slow to start, even if they were still running an older version of macOS.

As announced Tuesday, Apple made macOS Big Sur, version 11.0 of the operating system, available Thursday. At the same time as that introduction, several problems arose at Apple. For example, Apple Pay, Card, Messages, Maps and Apple TV devices had to deal with malfunctions, Ars Technica and AppleInsider write.

The most common problems were that users were unable to launch apps on macOS, or that apps were slow to start. That problem was not limited to users who had upgraded to macOS Big Sur, users with previous operating systems also experienced app problems.

The problems could be traced back to the way Apple validates apps, Mac developer discovered Jeff Johnson by using network tool Little Snitch. MacOS performs this validation by means of the trustd daemon. This is a process that has been in Apple’s operating system since version 10.12 Sierra, which runs in the background and which manages and verifies certificates. From macOS Catalina, notarization is mandatory for app developers and the certificate check is part of this, as is a check for malicious content. The daemon communicates with ocsp.apple.com, where ocsp stands for Online Certificate Status Protocol.

With the release of Big Sur, trustd was unable to contact ocsp.apple.com which led to slow startup of apps. Since dns lookups on ocsp.apple.com were successful, the apps kept trying. Without an internet connection, the apps would start normally and trustd blocking in the firewall would also work, were it not for the daemon that has been included in the ContentFilterExclusionList since Big Sur, writes security researcher. Patrick Wardle, and firewalls can no longer block them.