The default for Macs is to only show External disk and CDS, DVDS, and iPads on the desktop. 

But you can change that to add Hard disks (hard drive) and Connected servers (mapped drives)

1. Make sure to have all programs either closed or minimized so that only the Finder options on showing on the top menu bar of your desktop. 

2. Under the Finder tab select Preferences...

3. Then make sure all 4 boxes under Show these items on the desktop: are selected

If you had a hidden mapped drive, you should now see it on your desktop.