Vista: elevations are now blocked in the user's logon path
Without blocking applications from prompting for elevation in the user's logon path, both standard users and administrators would have to respond to a User Account Control dialog box on every log on. While this potentially becomes an annoyance for administrators, it is an unusable UI for standard users who cannot drive the UAC elevation prompt without having an administrator around to provide credentials. Furthermore, we advise users to be wary of prompts that appear without them taking an explicit action - and prompts generated at startup go against that advice.
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