Message Queue 4.2, like Message Queue 4.1, is installed by a relatively new installer, which also installs and upgrades the Java Enterprise System (Java ES) shared components required by Message Queue; for example, JDK, NSS, JavaHelp, and so on.
The new Message Queue installer and the older Java ES installer, which was used to install previous Message Queue versions, do not share the same product registry. If a version of Message Queue that was installed with the Java ES installer is removed and upgraded to Message Queue 4.2 by the Message Queue installer, the Java ES product registry might be in an inconsistent state. As a result, if the Java ES uninstaller is run, it may inadvertently remove Message Queue 4.2 and the shared components upon which it depends, even though it did not install them.
The best way to upgrade Message Queue software that was installed by the Java ES installer is as follows.
Use the Java ES uninstaller to remove Message Queue and its shared components.
Use the Message Queue installer to install Message Queue 4.2.