In my VS2012 project I use a third party dll. I do not add it into project references, but I have added its path into environment system variables (in Path), as suggested into the user manual of the third party software.

So inside my project I don't have any references to that dll, but only a .cs file where there are some [DllImport("xxx.dll")].

In the same solution, I've created an InstallShield project, to create a setup for my application. When I run the setup, I notice that the dll is copied into my application folder. That is not good for me, because if I try to run my application I have some compatibility problem with other dlls of the third party software. I've tried to remove the dll from the InstallShield project folder, but when setup runs, I see an error about dll missing.

If I remove manually the xxx.dll from my application folder, after the installation, it works correctly.

So, how can I avoid that xxx.dll is copied inside the application folder? Is there a way to tell to InstallShield that I do not want that xxx.dll is copied inside my application folder?