You hit onto something. The interop DLL version doesn't increment and that's why it's not getting replaced. Would the only way to resolve this be to use TLBIMP to manually generate the interop or is there a way to automate the incrementing?

>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?