macOS Sequoia causing issues with third-party security tools and web browsers

Apple's macOS Sequoia has apparently caused problems for users of third-party security products and web browsers because of firewall-related issues within the new operating system.

On Monday, Apple officially launched macOS Sequoia, making the new operating system finally available to the public. While the operating system introduces a variety of enhancements and features such as Apple Intelligence, the update appears to have caused issues and concerns for certain security-related products and applications.

According to a Thursday report from TechCrunch, macOS Sequoia has affected the functionality of different security tools, developed by CrowdStrike and SentinelOne, among others.

The report cites recent social media posts from different security researchers and posts from affected users on Reddit. Messages from software support accounts in a Slack chatroom for Mac Admins, warning users of issues with macOS Sequoia, are also referenced in Thursday's report.

Security software affected by macOS Sequoia

While the report says that the cause of the issue is unclear, it appears to be a network or firewall-related problem. In a Slack chatroom for Mac Admins, a CrowdStrike sales engineer said that there was "quite a lot going on with changes in the network stack" and that CrowdStrike support for macOS Sequoia would be delayed because of the changes within macOS.

The same CrowdStrike sales engineer also said that the company is "tracking similar issues with other vendors" and that they "have feedback and a case in to Apple." CrowdStrike is waiting for Apple to resolve the issue with a future macOS Sequoia update.

In the same Mac-related Slack channel, a SentinelOne support account also mentioned issues with macOS Sequoia and urged users not to update their operating systems. The company ESET also warned its users of a network-related issue with macOS Sequoia, urging its users to update their ESET software to the latest version, which is compatible with macOS Sequoia.

Security researchers say there's a firewall issue that affects DNS and web browsing in macOS Sequoia

While the issues in macOS Sequoia were noted by security software companies, individual security researchers have also experienced similar problems.

Two such security researchers, Will Dormann and Waclaw Jacek, have both reported firewall-related and DNS issues in macOS Sequoia.

Will Dormann said on Mastodon that he was experiencing issues with DNS and the macOS Sequoia firewall. According to the researcher, blocking incoming connections within the macOS Sequoia firewall can also block replies to DNS requests, causing issues. "Depending on your firewall config, silly things like DNS may stop working for some apps," the researcher wrote.

Dormann also pointed out a seemingly related issue that affects Chrome and Chromium-based browsers on macOS Sequoia. Blocking incoming connections for Google Chrome in the macOS firewall causes large downloads to stall.

Apple released macOS Sequoia on September 16, alongside iOS 18 and iPad OS.

Similarly, Reddit users have reported issues with the Firefox web browser on macOS Sequoia. One Reddit user experienced issues changing their Firewall settings in macOS Sequoia to allow incoming connections to Firefox, while others provided potential workarounds and solutions.

There are workarounds for such firewall-related issues, which essentially entail "poking holes in your firewall" as Will Dormann put it in his Mastodon posts. "Which clearly isn't as safe as having a working firewall, but we're at the mercy of Apple here," Dormann wrote.

Waclaw Jacek, another security researcher, seemingly corroborates the claims of firewall-related issues. The researcher said in a blog post that the macOS Sequoia firewall can sometimes start blocking access to web browsing.

It's important to consider that Apple has only released macOS Sequoia to the general public on September 16. Because the operating system is very early in its release cycle, there's always the potential for unpatched bugs or issues that Apple will address with future updates.

If you have experienced similar issues on macOS Sequoia with the third-party products and apps described here, AppleInsider recommends that you follow the instructions provided by the software's developers and customer support teams. For some users, this could mean sticking to macOS Sonoma for the time being.