I need to stop a service that was incorrectly installed on a prior version of the application. When installshield goes to upgrade it runs the uninstaller from the prior version first so it seems I can't add a custom action before that happens.
Is there a was to add a custom/action step that fires BEFORE the prior version's uninstaller kicks in?
If you're running new versions from the InstallShield environment, it could be InstallShield removing the old version first instead of your installer. You can turn this off using Tools > Options > Preferences > Uninstall before installing. Once you make that change, your new version will behave as it will out in the world.
Otherwise, if the old version is being removed, it's a major upgrade; so you should be able to put your custom code before RemoveExistingProducts to ensure it runs before the old version is removed.
If you do need to go down the custom action route, perhaps use a launch-an-EXE action that launches net.exe? (You'll probably want to add conditions to ensure it runs only when you want---not on uninstall, for example---but first things first.)
