phil wilson

The general problem you've got is that INSTALLDIR is not being preserved
after the installation, so if you ever cause new features to be installed
that are aimed at INSTALLDIR they will go to an unmodified INSTALLDIR. One
of the ways you can do this is have a type 51 custom action in the original
installation that sets ARPINSTALLLOCATION from [INSTALLDIR] after you've set
its value. This preserves the install location in a way that can be
retrieved later with a custom action vbscript that uses
Installer.ProductInfo (ProductCode, "InstallLocation") conditioned on
Installed.
Or the original install can have a registry entry that is set to
[INSTALLDIR] and a custom action that gets the value conditioned on
Installed. Or AppSearch can look for that registry value and you can have a
type 51 custom action that sets INSTALLDIR from it conditioned on the
property name (meaning that the AppSearch found the value).
--
Phil Wilson [MVP Windows Installer]
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