A group of researchers from Photonan American company dedicated to integrating AI agents into messaging applications, has found a surprising bug, or malfunction, in macOS It affects all versions of the operating system. Apple and, therefore, to all your computers. And it is that, If a MacBook, iMac, Mac mini, or Mac Studio is left on for more than 49 days, 17 hours, 2 minutes, and 47 seconds, it loses its internet connectivity and the only way to fix it is to restart it.
Photon encountered the problem when using a group of computers Mac to monitor services iMessage. The problem manifested itself when some machines, without further ado, suddenly stopped responding to network connections, although they were still responding to ping requestsa check message sent to a device to verify if it is still connected and responding on the network, which made the situation more difficult to diagnose. When responding, computers indicated that they were keeping their existing network connections active. And yet, there was no internet.
Photon technicians had to restart the machines to solve the problem and, after detecting that another group of computers was approaching 49.7 days of uptimethey verified that when the fateful moment arrived, the Mac that had to continually creating new connections, it would simply stop doing so without even showing an error.
The team discovered that the bug was related to an internal macOS counter that measures the time since the computer was turned on. This counter adds milliseconds and has a mathematical limit as it is designed with a numerical format that only allows you to count up to 4,294,967,295. When that figure is translated into milliseconds, the result is exactly 49 days, 17 hours, 2 minutes and 47 seconds. That is the moment when the counter reaches its limit and, instead of continuing to function as it should, enters a wrong state. From there, the system begins to miscalculate how much time has passed and loses the time reference it needs to manage part of the internet traffic well.
That error affects the automatic cleanup of network communications that have already ended. Normally, macOS removes these closed connections after a short time to make room for new ones. But, when the counter fails, the system believes again and again that those old connections should not be deleted yet, even though they are already finished. The result is that remnants of network activity accumulate until they occupy the available space. When it runs out, the Mac stops being able to open new communications over the internet and many network functions begin to fail, even though the computer appears to be on and responding to basic checks.
According to Photon, the only option is to reboot, although the team says it is working on an alternative solution. Curiously, this problem already occurred in Windows 98 and Windows 95also at 49.7 days, but Microsoft solved it in Windows XP.