Sorry for taking up the space here. Doing additional searches confirmed that others have seen this problem and that a workaround is:
Use the Go menu in Finder and "Connect to Server" by IP address.
[Now, since I'm the Windows/UNIX person helping out my Mac husband, I'll admit that it took me 20 minutes or so to find Finder's Go menu. Any one else in the same boat should look for the menu at the top left of the screen - perhaps far away from the Finder window itself.]