Why is iCloud not syncing?

I have iCloud installed and working on both my mac desktop and my mac laptop. I changed a file on iCloud on my desktop. When I log on to my macbook, the file has not been synced. I read somewhere that one can try turning iCloud syncing off and back on, but I got a message in System Settings that turning off iCloud drive would delete all the files on my laptop, and I don't want to do that.

BTW, I have all the latest software installed on both computers. All my google search turned up was how to turn on iCloud. But it's already turned on and the older files have apparently been synced. But not recent changes.

BTW, I logged on to iCloud.com and downloaded a copy of the file in question, and it has been synced on iCloud.com, but not on my laptop.