macOS 27-beta: Apparently file system issues related to Time Machine

Users testing the public beta version of macOS 27, also known as Golden Gate, have reported potential file system issues linked to Apple’s Time Machine backup system. Reports surfaced on platforms such as Reddit and other forums, indicating that under certain conditions, users may encounter file system errors due to improperly written metadata. These problems were initially identified in the third developer beta of macOS 27, which aligns with the current state of the public beta. In severe cases, data loss could occur. As of now, Apple has yet to respond to these concerns. It appears the issue may be connected to the use of Time Machine, though most affected users employ this standard backup solution. The file system corruption manifests in several ways. On affected systems, users have observed frozen operating environments or seemingly random restarts. Some applications fail to launch altogether. When running the `verifyVolume` command via the `diskutil` tool on the main volume (`/System/Volumes/Data`), users received responses such as “corrupted” or “notable errors.” A user named imajes on Reddit, who is currently collecting reports, noted that two affected machines had been updated from Tahoe to Golden Gate. He discovered incorrectly written xattr metadata using the `fsck` command. He documented how the system attempted to write a large number of metadata entries after updating from Developer Beta 2 to 3, but these failed to reach the SSD. Apple support reportedly advised affected users to wipe their systems and revert to macOS 26.5.2 using an existing backup. On the affected machines, Time Machine was configured to use an external destination, typically a network-attached storage (NAS) device. These backups appear to be impacted as well. In one instance, attempting to mount the backup in read-write mode triggered a kernel panic. The exact nature of the problem remains unclear. However, a guide has been shared on Reddit instructing users on how to check whether they are affected. This information will be collected to provide feedback to Apple. It is still uncertain how widespread the issue is. Nevertheless, the incident underscores the importance of exercising caution when working with beta software. Users are strongly advised against handling real data on beta versions and should avoid installing public beta releases on production machines. Regular backups are essential. Despite previous stability reports regarding iOS 27 and macOS 27 beta versions, this does not guarantee future reliability. Additionally, setting up a separate Apple account for beta testing is recommended to prevent real-world data from being compromised. Apple continues to monitor the situation, though no official statement has been issued. The company may take action once more detailed reports are compiled. Until then, users remain advised to proceed with caution and ensure robust backup strategies are in place. The ongoing investigation into the file system anomalies highlights the complexities of maintaining compatibility and performance in rapidly evolving operating system updates.