If you leave your Mac running for weeks without restarting, you might run into an issue with your internet. Folks over at Photon.codes recently discovered a bug in macOS, which causes network connections to completely break down after roughly 49 days of continuous uptime. Your machine might appear to be working perfectly fine offline, but web browsers and other connected applications will suddenly fail to load anything.
Apple has not patched this kernel glitch yet, leaving its users to fix the problem themselves.
How the timer issue breaks networking
The problem revolves around an internal counter called “tcp_now.” This specific counter tracks exactly how many milliseconds have passed since you turned on your computer. It uses a 32-bit integer format, which has a strict mathematical ceiling. The maximum number equals 49 days, 17 hours, 2 minutes, and 47 seconds.
Once the counter hits this limit, it should reset to zero. The core code inside macOS fails to handle this transition properly. The system becomes confused when checking old connections and deciding what to do with them.
What exactly causes the ports to jam up
Whenever your computer talks to a website, it opens a temporary networking port for that exchange. Once the data transfer finishes, the port should close and be wiped away so the computer can recycle it later.
Because the internal clock math breaks exactly at the 49-day mark, the system starts failing every time it checks if a closed connection should be deleted. All those temporary ports get permanently stuck in a frozen state. The longer you use the internet, the more stuck ports pile up in the background.
Eventually, the computer simply runs out of available spaces to process new network requests. How fast this crash happens depends on how heavily you use your internet.
Why restarting is the only reliable fix right now
The source confirmed this behavior by setting up test machines and pushing them right to the 49.7-day limit. Every time, the machines stopped making new network connections without showing any warning messages. The computers would still answer basic network pings from other devices, but normal web traffic was dead.
Since Apple handles these core networking tasks deep within its system architecture, you cannot download a quick fix from an outside developer. The only way to clear out the jammed ports and reset the timer back to zero is to restart your machine.
For home users, shutting the computer down once a month avoids the bug entirely. Server operators will have to schedule regular reboots until an official software update arrives to correct the code.
Why does your title say “MacBooks”? Photon specifically says ALL Macs and give examples of affected machines that are not MacBooks (Mac Pro and Mac Mini).