File copied to Debug folder is automatically deleted when the C# program launches

Question

I am using Visual Studio 2012 to build a WPF program. There is a DLL compiled from C that I use DllImport to call. The Dll is added in the project and marked as

• Build Action: Content
• Copy to Output Directory: Copy always

When the project solution is built the dll is copied to Debug folder with the .exe generated by Visual Studio successfully. However, when i run it, either by double click the generated .exe from File Explorer or "Run" in the VS debugger, the dll suddenly gets deleted by itself.

Why?

Answer 1

If it does this when running from File Explorer, then either

• Your anti-virus program is deleting the dll when you try to access it

or

• There must be code in your program to delete files in the current directory.

Answer 2

After many tries I've found some pattern which can be also a workaround. Assume we have 3 projects, A, B and C.

1. A depends on B; B depends on C - problem exists
2. A depends on B and C; B depends on C - problem disappears

Maybe it'd help someone to track the reasons.