2 ways:
1. Unload xDesktop (!netunloadmodule xdesktop-1.7)
Then open the xDesktopConfig File in a Texteditor
Remove the line with "::{208D2C60-3AEA-1069-A2D7-08002B30309D}"

2. Simply call a !xdesktopcreate replace .desktop

Advantage of method 1, you keep your customized icon positions.
Advantage of method 2, it's just one bang call.

Choose to your liking :)