Q:

Inno Setup and Copying a file

I have an installer that is working just fine. What I would like to do is copy a DLL that is part of the installed application to another folder. For example I am installing the application on E:\Folder, but I would like to copy a DLL from that install to E:\public. 
Is it possible to have Inno copy a file to another folder as part of an install? 

A:

If you want to copy that library into a folder which is a subfolder of the parent folder selected by the user on the Select Destination Location wizard page, then you should specify the path relative to the {app} folder for the DestDir parameter of your [Files] section entry for that library. In script it would be something like this:
[Files]
Source: "App.exe"; DestDir: "{app}"
Source: "Library.dll"; DestDir: "{app}\..\Public"

Just to make it clear, if the user selects e.g. this folder:
C:\Program Files (x86)\App Folder

Then the library will be copied to this folder:
C:\Program Files (x86)\Public

