A database with the same name exists, or specified file cannot be opened, or it is located on UNC share

Question

Hi,
I am getting this error:
An attempt to attach an auto-named database for file D:\MyApp\Source Code\bin\Debug\db_Myapp.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
Any idea? Please help:)