Windows – Install and run 32 bit on 64 bit machine

I want to make sure that on 64-bit Windows, 32-bit application can be installed/run without any issues? And it is guaranteed by Windows backward compatibility?

For example, any application (e.g. Microsoft Windows Media Encoder 9) which runs smoothly on 32-bit Windows 7 can run smoothly on 64-bit Windows 7.

I am developing some software and actually my question is whether release x86 version is ok for both 32-bit and 64-bit Windows 7. If WOW could guarantee it, it could save my work to package different binaries for different platforms.

Solution:

No, there is no guarantee, and it isn’t difficult to find examples of 32-bit applications or libraries not behaving as expected when running inside WoW64 (Windows on Windows 64-bit, the 32-bit environment that allows 64-bit versions of Windows to run 32-bit applications).

In general, they’ll work fine, but it’s certainly not a guarantee.

Also, this belongs on superuser.com; this isn’t software development related.