File.Copy Simply Doesn't Work by Itself VS2012 Excel

Question

Simply copying a file from one directory to another using file.copy(sourcefilename, destfilename, true) never works because the sourcefile is always in use! Always!
If I run this simple code in debug it works fine, but without debug the source file is ALWAYS in use.  I used the file.copy method back in VS2005 on xml documents and it worked fine back then.  Now, using Excel files, it NEVER works.
Clearly I'm missing something.
Ross

Answer 1

I assume you are missing something. I created a test project with the following.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim folder As String = My.Computer.FileSystem.SpecialDirectories.MyDocuments
Dim sourcePath As String = IO.Path.Combine(folder, "Test.xlsx")
Dim destPath As String = IO.Path.Combine(folder, "ExcelTest", "Test.xlsx")
IO.File.Copy(sourcePath, destPath, True)
End Sub
As long as Test.xlsx exists in My Documents and there is a folder called ExcelTest also in My Documents, the file is copied to the ExcelTest folder. It works both within Visual Studio and when running the compiled exe outside Visual Studio.
Is it possible that the file really is in use?