Photostream takes 100% CPU, can't turn it off.

[coincoin]

I have Mavericks on both my imac and my macbook air. When I run Activity monitor on either computer, "Photo Stream" often takes 100% of CPU. It runs for about 5 seconds, disappears for 5 seconds, and reappears for 5 seconds. I have no use for photostream, and this doesn't seem like normal behavior.

I checked that photostream was deactivated in both iphoto and system preferences. I tried disconnecting from iCloud, but did not change a thing. Any suggestions?

 

[coincoin]

fixed

Update: the problem was apparently caused by my having uninstalled iPhoto, and photostream desperately trying to find it.

Following this thread:
http://forums.thedigitalfix.com/forums/showthread.php?t=628362 ,

I booted in safe mode, rebooted normally, and now all is fine.

If anyone knows what the safe mode booting does to fix the problem, I'd be curious to know.