Is there a way to pause iCloud Drive?

Solution 1:

I'm not sure how it exactly accomplishes it, but take a look at TripMode. It offers the functionality you're looking for, and even automatically switches based on the network you're on.

Solution 2:

I am using this trick to temporarily disable or enable Desktop and Documents synchronization (Tested on macOS Sierra 10.12.6)

• Enable Firewall if it is not enabled.
  System Preferences > Security & Privacy > Firewall
• Add Finder to the firewall list
  Press the plus button and search for Finder app.
• Select "Block Incoming Connections".
• When you are ready to re-enable the synchronization just select "Allow incoming connections".

This method is acceptable for me because I just need to enable the synchronization time to time
(I do not own any other Apple device thus I use iCloud synchronization like an online backup).

Note that when Finder is blocked you will stop synchronization FROM your Mac to iCloud. However, changes made in the cloud will be synchronized to your Mac (Eg. using the iCloud web interface or other device).