Can't seem to find anyone with the same issue by searching. Anyone have the process "xpcproxy" take up over 100% CPU after installing Sierra? It didn't seem to start at first, but suddenly started sometime after. This is on a 2010 MacBook Pro 15" with an SSD. The same process seems to be sitting at around 200-400 MB of RAM but holding steady and not climbing. Can't tell if this is some sort of normal indexing type process or not since I've found no matches for similar cases. EDIT: I just clicked on the battery icon in the menu bar and it's saying that "Photos Agent" is taking up significant battery. I'm guessing xpcproxy has to do with Photos then. Guess I'll just continue to let it do its thing for a while. EDIT 2: Found out that only iStat Menu is calling the process xpcproxy. Activity Monitor calls it photoanalysisd, which the name alone kinda gives it away, but also a search reveals other people have encountered too. I'd just delete this post, but I can't see to find a way to do that, so I guess here it is for posterity.