Hi Sherry, I've had the same problem. I created the application in Access 2010 and sent it to users who had 2007 installed on their PCs. It seemed to work fine up until last week as I thought that 2010 was backword compatible to 2007. However, this week somehow my file got changed from an .accdb file to and .mdb and my users still could not open the file I'd sent them.
Pat,
I tried what you suggested but still no success. I think this all started when I tried to use the 2010 Ribbon customisation which messed up something. Problem is 2007 ribbon customisation does not appear to easy as I do not know XML and do not have 2007. Any other ideas as to how I get round this problem.
Thanks in advance, ekayp