Sometimes the list of shared computers on the network will not refresh within Finder.
To fix this issue, re-launch the Finder, from the dock. You can do this by:
– Hold down the Alt key and right-click on the Finder icon in the dock. The pop-up menu should include Relaunch as the last item. Click on that and it will re-launch Finder, which takes just a second or so.
Hope it helps!