I have Mac OSX Yosemite, 10.10.1 and halfway through last month my computer decided to download about 500MB every day. I even quit all programs and it still downloaded 447MB. I am seeing this number in the network section of Activity Monitor and the Process name listed is nsurlsessiond. What is this downloading and how do I stop it?
nsurlsessiond deals with iCloud & also Spotlight.
for Spotlight - Prefs > Spotlight > Search Results & switch off Spotlight Suggestions & Bing Web Searches.
iCloud, some suggestions…
Disable iCloud Photo Library, Photo Stream & iCloud Photo Sharing from
System prefs > iCloud - Photos [or equivalent, I can't remember the precise layout before Photos app]
If you have an iPhone, the same settings are in Settings > iCloud > Photos
nsurlsessionhd can be disabled with
sudo launchctl unload /System/Library/LaunchDaemons/com.apple.nsurlsessiond.plist
BUT you run the risk of some Apple (and maybe non-Apple) apps not being able to connect to the internet, specifically App Store, iTunes, software updater, etc. If that is the case re-enable by replacing
load in the command above.