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.


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.



This mechanism is not included on Windows 10 on ARM.