opening recent library option no longer available

Endnote 6 working great, until a few days ago when I am unable to open library unless I do into Mac applications.

I open endnote > file>open recent> get a greyed out ‘clear menu’. (see screen shot)

I have had this version of endnote for years without any dramas whatsoever, this problem occurred last week

Is anyone able to shed any light or solution to this problem please?

many thanks S

I have mac os 10.8.5