Question : Why can I not open an accde file on another computer?

I created an Access 2007 (accdb) file. I then compacted/repaied etc, and made it into an (accde) file . Thirdly, I packaged it and sent it to a user. The user was totally unable to open and extract the file (seems like some security setting). I then sent them the (accde) fiel, and the same thing happened- they were unable to open the file and the same secutiry message came up. Finally, I had to send the (accdb) file, which opened normally!
I would like for my user to use the (accde) version.
Why is this happening? and how can I fix it?

Answer : Why can I not open an accde file on another computer?

It suggest that you are using A2007 SP1 and your user is not.