im a newbie why i cant open a file it says "not a design file"

first you need to tell us what version  of  microstation  because  it can make a big difference to how to answer you, this is  part of  the  rules for using this forum,  

Next you  have tell us  how you are trying to access the  file , ie windows explorer, microstation icon > microstation manager, and  what extension does the  file  have etc, did you create the  file or  is from another  user?

first you need to tell us what version  of  microstation  because  it can make a big difference to how to answer you, this is  part of  the  rules for using this forum,  

Next you  have tell us  how you are trying to access the  file , ie windows explorer, microstation icon > microstation manager, and  what extension does the  file  have etc, did you create the  file or  is from another  user?