Try to find the
global.py file, this will probably find it - press Winkey+R. enter
%appdata%\calibre, press Enter and an explorer window will open and you should find it there.
Open it in a text editor and look for
library_path, you should see something like this:
Code:
# library path
# Path to directory in which your library of books is stored
library_path = u'D:\\Calibre\\Libraries\\Books'
D:\Calibre\Libraries\Books is the location of my most recently used library
BR