Library Will Not Show References in Alphabetic Order

I work on EndNote 7 with Word Office 2011.  My machine is a Mac OS X Version 10.9.1.  I imported an Endnote Library from my old machine, a PC Windows made there with an old version of Endnote.  After a while it became apparent that the Library was not showing the authors in alphabetical order.

After three hours of checking how I had entered the authors’ names and trying to work the sort function I gave up.  It was not a big library (less than 100 items) so I decided to build a new one on my new machine, inputting the data anew.  And the same problem happened again.  Only three entries made - and the authors’ names are not listed alphabetically.  The sort function appears to work by date, but not authors name.

Any suggestions will be gratefully received.  Many thanks in advance

Be sure the authors are entered as Lastname, X. Y. and that they are on separate lines. If they are, try clicking the Author button at the top of the author column. See attachment.

Many thanks for this.  The problem seems solved.