My setup includes a merge module that installs some dlls to the system folder and one dll to the gac. After performing a major upgrade the dll is removed from the gac. Theother files are correctly reinstalled. Note: the previous setup/merge-module has been created with a lower Installshield version.
Yes. This is a known issue, not with InstallShield, but with msi, and it is still not fixed. In your major upgrade, be sure to select "Install setup then remove unneeded files" rather than "Completely uninstall old setup before installing new setup". This will likely fix the issue.
