Answer:

There are two things that can cause the Windows userid to be disabled in the window that lets you connect to the filer (the window with "434" in the upper left-hand corner):

1. If your filer isn't a domain member, then you can't connect with your domain userid. You can only use a NetApp id. For that reason, the Windows userid displayed in the window is disabled.
2. If your Windows userid (or a group your Windows userid belongs to) isn't authorized to use Folderscape, then it will be disabled on the connect window. To enable your userid to connect to the filer, connect to the filer using the "root" userid, then choose "Folderscape Security" from the "Tools" menu.