iCloud gets stuck syncing in Sierra, how do I fix I recently upgraded from Yosemite to Sierra.  I have ~ 2.5Gb of data on my iCloud Drive.  I am NOT using the Documents and folders sync, photos sync, or any of the other special folder sync options available.  The exception is that I am syncing preferences.  As I have said I do have two folders that sit in the iCloud Drive that are not part of any of the special folders.  

The problem is that after the initial sync, any change in those files/folders siting on the iCloud Drive get stuck syncing.  The icon animation (pie chart) and the text that appears under the file/folder indicating the progress cycles between 0 and ~90%.  It never gets to 100%.  

On previous occasions restarting fixed the problem, but only temporarily.  Currently, I have a 53Mb file that has been syncing for 4 days now.  I have tried restarting to no avail.  While signing out of iCloud, brings up the message, "iCloud need to finish updating before continuing with signing out".  But it never finishes.

Additionally, I have tried to upload the file manually to iCloud via Safari, this process is also stuck currently.

Anybody have any ideas of what might be going on?
Well it seems that Kaspersky Internet Security (16.0.0.245b.a.c) is the problem here.  I found that changing the "Check secure connections (HTTPS)" setting allowed syncing as usual.  This setting is found under the Protection tab in Preferences, under Web Anti-Virus.  I changed the option from "Check secure connections (HTTPS)>always", to "Check secure connections (HTTPS)>Only for Parental Control, Safe Money, and Privacy Protection".

I also added icloud.com to the Trusted zone and Web site tracking exclusions, but I do not believe these changes were necessary or had any effect."