Further comments in bug #728700 led me to searching Google.
It appears that LightDM may be a red herring for this problem.
It seems to be (as far as I can tell — I may be wrong) that this is caused by glib when cancelling a file being copied, as per comment #60 and others.
Further comments in bug #728700 led me to searching Google.
It appears that LightDM may be a red herring for this problem.
It seems to be (as far as I can tell — I may be wrong) that this is caused by glib when cancelling a file being copied, as per comment #60 and others.