There are currently 600 photos in the process of being uploaded to my iCloud photo stream in iPhoto. I would like to stop the uploading process...how do I do that?
iPhoto '11, OS X Yosemite (10.10.2)
I assume you are referring to Photos app on your Mac & not iPhoto.
See this…
http://sixcolors.com/post/2015/04/photos-for-macs-unrestrained-icloud-uploads/
You can pause the upload if you want to delay it. Otherwise you need to disable the iCloud photo library if you do not want to use that feature.
Stop your iCloud sync by Going to System Preferences/iCloud and unchecking the applicable application.
how do I stop uploading of photos to iCloud in iPhoto
