I've found that the H2 API call used to "plug-in" a collection (into another collection such as ms.vsipcc.v80), can fail under Vista User/UAC log-on. Also the H2 API does not give you the choice to register as either ALL USERS or CURRENT USER. The H2 API simply sniffs the environment and makes the decision for you. So under Vista User log-on, collections can be registered incorrectly under CURRENT USER instead of ALL USERS. Your main setup program may not marked as "run as administrator". To solve these problems make sure your main setup program is marked as "run as administrator" using a manifest file. Any MSI or EXEs your setup program runs (and any apps they run) will also be automatically elevated. Note that although it is possible for Windows to detect that an application is an installer and automatically elevate it, you should still explicitly elevate applications that need to run in Admin mode (using a manifest file). This is because this auto detect & elevate feature in Windows is controlled by a Group Policy and may be disabled in an enterprise environment. Its also a bit hit and miss. Helpware Article: Vista Readiness and Collection Registration