Do you get an error message?
If Outlook is already running when you attempt to instantiate your object, and the error message is something like "RPC server unavailable", then it might be an issue with user privileges ; your application is running with different privileges than the running Outlook instance.

>I have seen messages about this before, but can't find them. On some machines lo = Createobject('outlook.application') fails, even though Outlook 2010 is installed. Any tips?