My issue was the same, only in "Numbers", Thank you VikingOSX. Your answer has resoved a very stressful situation with me. I worked for hours on a file that suddenly, for no reason dissappeared and I could not find it. PANIC MODE! Thanks to you, I can now access this file. Somehow my Numbers program upgraded to a newer version (unknown to me how this happened). When I continued in this new version, changes were no longer recognizable in the 09 version. My 09 version loads when I click on the icon in the program bar at the bottom of the screen. The 09 version does not recognize any new files or changes made in the new version. I've also found that If you go into "Finder", then Click on "Applications", then "Numbers", The newer Version (V3.6.1) Loads and you can access the file you've been working on. Also in "Applications" you can still access the 09 version in the "09 IWorks" folder. Hope this helps all the others who are in panik mode because of the loss of their painstakingly worked on files.