I'm getting fed up with this... My iMac won't upload anything, whether it's pictures, music or movies, to Dropbox, Facebook, Gmail, or anything else. It's not my network since my MacBook Pro uploads fine and I've tried the iMac on several different network connections. Speedtest.net does fine with ping and download, but once it gets to upload it just freezes at 0.00. Once in a blue moon, when it gets to upload, the meter gets a sudden surge to about 0.30 Mbps, after which it slowly decreases to 0.00, and freezes there. A while back my iMac's internet (download and upload) was lagging, so I did a full clean install. It worked fine for a while, but, lo and behold, after a month or so my upload completely stopped working. I've deleted the whole SystemConfiguration folder and created a new location. I've tried using all sorts of DNS servers. I've tried different MTU values. I've tried different browsers. I've tried everything. Someone please tell me there's a way to fix this. I'm running OS X 10.9.3 (Mavericks) on a 21.5 inch Mid 2011 iMac. Someone, PLEASE PUT ME OUT OF MY MISERY!