Major Upgrade not using same INSTALLDIR as previous version
I'm missing something, I'm sure, and it's causing us grief in trying to field an upgrade to an application.
On systems with a C: and 😧 drive, our X.0 version is installed in C:\yyy. When we run our Y.0 upgrade, it's selecting D:\yyy as the installation directory, and this is causing some grief. A lot of grief, and confusion. It's supposed to uninstall the previous version and then do a full install of the new version. The INSTALLDIR property for the new install is still set to C:\yyy.
What drives that selection of the target drive, and why does it not want to overwrite the existing version? (That may be the logical bit I'm not getting)
Is there some value I can get to reset the target to the existing location for certain?
Turned out to be mostly user error and ignorance. The previous installer had some magic custom action that forced the install directory, and that had not been included in this release. Plus I learned about ROOTDRIVE and the default Windows Installer behavior to select the writable drive with the most space as the default target when nothing else is specified. So problem is solved.
