Consider the following scenario. On a computer that is running Windows Vista or Windows Server 2008, you successfully install an earlier (legacy) version of a particular wave driver. In Device Manager, this driver is shown as being installed correctly. However, under certain conditions, an application that has to load this wave driver cannot find it.
If you use a debug tool, such as WinDBG, to troubleshoot the issue, you will notice that the user-mode wave driver does not load as expected.