I was asked the following question recently: What are the minimum permissions necessary I need to grant a user in order for that user to be able to access the data in another user’s mailbox?
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Updated Jul 01, 2019
Version 2.0
Blog Post
We are having a problem where we are granting a user in one domain Send As rights to a mailbox in another domain (same forest) and the permission keeps "disappearing". I have tried it with different users and the same thing happens. We are on Exchange 2003 SP1.