Use Isolated Applications and Side-by-Side Component Sharing to Reduce DLL Conflicts

If your application must consistently get the version of a component you have tested, it is possible to isolate the application with a copy of the tested component. This prevents your application from ever getting an untested component update that could cause a problem in the future. For more information, see Isolated Applications and Side-by-side Assemblies.

Windows 2000 and Windows XP enable you to create isolated applications (both IIS and Windows-client applications) and shared components. Developing isolated applications and shared components improves your application's reliability, stability, and resistance to DLL version conflicts by accomplishing the following:

• The application always uses the versions of shared files with which it was deployed.
• Installing the application does not overwrite other versions of the shared files by other applications.
• Subsequent installations of other applications using different versions of the shared files cannot overwrite the files used by this application.

When you use Windows Installer to install your application, you can specify that the installer copy the critical files (commonly shared DLLs) into the application's folder rather than to a shared location. This private set of files (DLLs) are then used only by the application. For more information, see Isolated Components.