I've had my Macbook Pro for about a year now. It is a late 2013 Retina model running Yosemite. Until a few days ago, its Wi-Fi worked fine. However, after the 10.10.5 update, its Wi-Fi has become very slow and drops packets unless I'm a foot away from my wifi router. When I'm in my usual location of the next room, ping times go up to hundreds of milliseconds.
shanglin$ ping 192.168.1.1 PING 192.168.1.1 (192.168.1.1): 56 data bytes Request timeout for icmp_seq 0 64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=944.501 ms 64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=325.487 ms 64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=78.760 ms 64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=126.286 ms Request timeout for icmp_seq 5 64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=41.813 ms ^C --- 192.168.1.1 ping statistics --- 8 packets transmitted, 5 packets received, 37.5% packet loss round-trip min/avg/max/stddev = 41.813/303.369/944.501/335.189 ms
None of the other devices on my Wi-Fi network are having a problem. I've tried removing plist files from SystemConfiguration, and I've turned off Bluetooth.
My Wi-Fi router is a Cisco E1200 running 802.11n on the 2.4GHz band. I don't think it can run on the 5GHz band. I've tried updating the router's firmware to the latest, but it has not helped.
Any suggestions that could help?