I have a VB6 app that utilizes a non-activeX DLL (non-registering). It's declared via the classic Public Declare Function "Function Name" Lib "Library.DLL" syntax. On my dev machine (XP) it works fine but when I deploy to Vista or Win7 I'm constantly greeted with a Run Time Error 48 - File Not Found for the DLL in question. I have tried copying that DLL to every directory I can think of including every environment path on the test machine and the app path too. These are all 32-bit test environments so it's not a SysWow64 issue. Possibly throwing a wrench into the mix is the fact that the application in question is an Outlook COM Addin. I managed to install VB6 on Win7 and was able to run a tiny sample app that utilizes this DLL (outside of the Outlook process) so I know it works PROVIDED the DLL is located in App path. If I call App.Path from my DLL when I run it on the test environment it shows, to no surprise, my installation directory however the DLL is there. I tried turning off UAC. I tried making the App.Path directory permissions open to everyone, still no dice.