I last used my MacBook Pro with macOS 10.13.3 yesterday morning (5/4/18), shut down my MacBook pro like usual, and powered it on today (5/5/18). When I looked into Finder today, all my files under the Desktop folder where missing in both Finder and iCloud.
MacBook Pro
See this article Get help with iCloud Drive - Apple Support
What if I don't see all of my files?
When you turn on iCloud Drive, any documents that you already store in iCloud automatically move to iCloud Drive. You can see your files on iCloud.com, in the Files app on iOS 11 and later, in the Pages, Numbers, and Keynote apps, or in the iCloud Drive app on iOS 10 and iOS 9.
If you don’t see your files in any of those locations, make sure that you set up iCloud Drive on all of your devices. If you don't see the files from your Mac Desktop and Documents folder on iCloud.com, go to System Preferences > iCloud, then click Options next to iCloud Drive and make sure that it's turned on.
If you need to access a file that you deleted within the last 30 days, you can get it back from the Recently Deleted folder in the Files app, or on iCloud.com. After 30 days, your files are removed from Recently Deleted.
See this article Get help with iCloud Drive - Apple Support
What if I don't see all of my files?
When you turn on iCloud Drive, any documents that you already store in iCloud automatically move to iCloud Drive. You can see your files on iCloud.com, in the Files app on iOS 11 and later, in the Pages, Numbers, and Keynote apps, or in the iCloud Drive app on iOS 10 and iOS 9.
If you don’t see your files in any of those locations, make sure that you set up iCloud Drive on all of your devices. If you don't see the files from your Mac Desktop and Documents folder on iCloud.com, go to System Preferences > iCloud, then click Options next to iCloud Drive and make sure that it's turned on.
If you need to access a file that you deleted within the last 30 days, you can get it back from the Recently Deleted folder in the Files app, or on iCloud.com. After 30 days, your files are removed from Recently Deleted.
Eric ..
Visit the App Store and update your macOS to v10.13.4 then restart your Mac then check your files in the Finder.
Missing Files under Desktop Folder in both iCloud and Finder
