Cannot open an .MDB FIle - Microsoft Community
answers.microsoft.com › en-us › msofficeNov 25, 2015 · What isn't working when I click on the .mdb file I get a security prompt and the file won't open. I added folder location as trust location, and still won't open. I have another program that doesn't support the .accdb format yet. I can import all tables and queries from the .mdb into an accdb file so I know everything is working.