I created a database in Access 2007 but my client has just upgraded to 2010. I have not upgraded yet. My problem is that when I took a copy of the program home so I could tweak it some, my 2007 will not open it. I get a message that the format is uncrecognizable although the extensions are the same. With earlier versions of Access, I have noticed some loss of function or changes in the appearance of forms, but I have never experienced a databse being unrecognizable. The options under 2010 allow a database to be saved down to 2000-2003, but not 2007. I can't figure how I can work on this at home unless I go ahead and upgrade. Please advise.