One of the most annoying issues I have come across so far and I’m going to blame the apple update to macOS Sierra 10.12.1, this one took a lot of troubleshooting as it wasn’t immediately obvious. Generally, macs are pretty harmless creatures so that was the last place I would expect this kind of issue, or is it, so naive!
Setup – Running a network with multiple PC computers and one Apple MacBook pro, connected to a Windows Essential Server 2012 r2, 24 port gigabit switch Draytek Vigor ADSL2+ Router.
Problem: The internet connection all of sudden had become intermittently slow probably over a period of 1-2weeks, some days it would be fine getting 15mbit down then the next day it would be horrendously slow getting 0.5mbit, and some days it would fluctuate anywhere in between.
Immediately I thought it must be the ADSL connections so contacted TPG to run line tests, isolated devices on the network, had only one device connected to the router, all the general troubleshooting stuff but couldn’t pin point the problem, even swapped the router for a new one but still no good. Had the TPG technician out to check the lines from the exchange to the pit, pit to the house and first point to the router, nothing unusual.
Resolution: Eventually, I noticed the internet would come good around 4-5pm and it just so happened the was generally the time when the Mac user would go home, finally a sign! To cut a long story short I couldn’t find anything dodgy running on the Mac so decided to start with creating a new Mac user profile and copy all the data from the old profile across. This seemed to do the trick the connection speed test immediately jumped up to the high 13 and 14mbps, surprisingly if I turned the Mac off completely I would get 15mbps consistently.
I haven’t been able to find the actual cause on the Mac but for now the new profile has done the trick, internet speed has been restored and everything seems happy again. If you’ve been having similar issues I hope this helps and if you’ve taken it a step further and run some packet inspection and worked out what it is would love to know where the issue was.