Qsys project status indicates unsaved; even after I explicitly save (12.1)

My Qsys project appears to be unsaved even after I explicitly save via the file menu.

I know this because

1) there is asterisks (*) beside the file name, which by convention indicates an unsaved file

2) when i go to generate the system; Qsys asks 'Save Changes to sys_top.qsys?'. I click save, but it does not seem to complete. Then I get the message 'Error: the system must be saved before generating'

There do not appear to be any error in the qsys log; only warnings

I did not have this issue when using Quartus 11.x

Any ideas?

-matt