Guessing here...

Is it in use?
Did the version number get incremented?

>We have a VB.Net service project that uses reg-free com on a com dll created in Visual Foxpro. The interop dll gets created fine during the build, and gets deployed fine on a clean install.
>
>However, if an older version of the service is installed and we attempt an upgrade install, the interop dll does not get overwritten.
>
>Any ideas as to why this is happening?