xpcproxy using all my bandwidth I have recently installed an SSD in my iMac and restored my backup using SuperDuper!. Since then, xpcproxy seems to randomly download stuff and uses all my bandwidth for minutes on end. What would be the reason?

I am running the latest version of El Capitan (yesterday's update).
In my case, it was nsurlsessiond (by sudo lsof | grep -i nsurl)

Fired up Charles with https MITM'ing, but didn't find anything talking to Apple (but it wasn't making any new connections to intercept).

It seemed to go away after a little while.

EDIT: After sleeping and waking it up with Charles running, xpcproxy showed it was downloading pictures from iCloud ([redacted].icloud-content.com).

(xpc services need some better monitoring tools and/or they're not well-known.)