I have a local file for the NorthWnd database that was copied to the bin\debug folder of my project. When I run my ProductsForm, I immediately see an error that states:

Unable to copy file "C:\Users\Cecil\Documents\Visual Studio 2008\Projects\C-Sharp Class\
Chapter5\Project6\NORTHWND.MDF" to "bin\Debug\NORTHWND.MDF". The process cannot access the
file 'bin\Debug\NORTHWND.mdf' because it is being used by another process.

It shows the same error for its accompanying LOG file.

I've seen this error before on the Internet and looked it up again on Google only to see lots of reasons for why this could happen, none of which seem to apply.

I am not using SQL Server to access the file at all right now, so why this error?