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Macs Face Network Meltdown After 49 Days
9 Apr
Summary
- A macOS bug causes network failure after exactly 49 days of continuous operation.
- The issue stems from an integer overflow freezing the internal TCP timestamp clock.
- Rebooting the Mac is the only temporary solution to restore networking functionality.
A peculiar bug has been identified in macOS that causes networking capabilities to cease functioning after a specific uptime. This temporal anomaly occurs exactly 49 days, 17 hours, 2 minutes, and 47 seconds into a Mac's continuous operation. The underlying cause is an 'integer overflow' that effectively freezes the system's internal TCP timestamp clock.
When this clock stops, existing network connections fail to expire correctly. Consequently, ephemeral ports become exhausted, preventing any new TCP connections from being established, although basic ICMP (ping) functionality remains. The only immediate remedy for this networking shutdown is to reboot the affected machine.
This discovery was made by Photon, a company developing AI agents, while monitoring Apple's Messages service. They successfully reproduced the glitch on multiple systems. While unlikely to affect average users, this bug could impact servers and other systems that operate continuously for extended periods.
The integer overflow vulnerability is not unprecedented, as Microsoft's Windows 95 experienced a similar 49.7-day crash due to a kernel timer overflow. Photon is reportedly working on a software solution to avoid the need for reboots, and an official fix from Apple is anticipated.
