Application Installation on 64-bit Systems
The 64-bit Windows Installer can seamlessly install 32-bit MSI-based applications on 64-bit Windows. For older applications that use a 16-bit stub to launch a 32-bit installation engine, 64-bit Windows recognizes specific 16-bit installer programs and substitutes a ported 32-bit version.
16-bit DOS, Windows, or OS/2 applications often use a 16-bit stub to check the machine type, then launch a 32-bit installation engine to actually perform the installation. To enable installation of applications that use this technique, 64-bit Windows substitutes 32-bit versions for the following 16-bit installer programs:
- Microsoft Setup for Windows 1.2
- Microsoft Setup for Windows 2.6
- Microsoft Setup for Windows 3.0
- Microsoft Setup for Windows 3.01
- InstallShield 5.x
The list of substitutions is stored in the registry under the following key: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\NtVdm64.
Note This mechanism is provided only for compatibility with 32-bit applications that use the 16-bit Microsoft installer programs listed in this topic. Addition of third-party installer programs is not supported.