Problem
Desktop icons or Fences are missing.
Solution
First, as a test, disable the quick-hide feature:
If this does not help, please make sure you have not inadvertently put the Fence on an alternate Desktop using Desktop pages. Disable Desktop pages to see if the Fence \ Icon is returned to your main desktop:
Automatic Layout
If all else fails, try evoking the Automatic Layout option in Fences:
https://support.stardock.com/space/SHC/1331396652
The restoring a recent Fences Snapshot:
https://support.stardock.com/space/SHC/1331331082/How+do+I+use+snapshots+in+Fences