i successfully imported about 100 pictures into lightroom from an external disk file. When I wanted to import the rest of the pictures from the same file, lightroom did not import. On the import command it just sat there, indicating zero imported files and when I selected the x in the window, it showed "there are no files to import"; sometimes I had to force quit the program. Now it will do the same thing with any picture file I select. It will not import any file, on the computer or on an external file. Restarting does not help.