Solution:
The
default "Save As" dialog in Acrobat DC is different than the dialog
that you've had in earlier releases of Acrobat, it also allows you to
save to the cloud and previous locations you've saved files to. It is
possible that when Acrobat tries to connect to "the cloud", it runs into
problems. You may want to try to turn this feature off to see if that
brings your save as dialog back: Open up Acrobat's preferences, then go
to the "General" category and deselect "Show online storage when saving
files":
