No email filtering system is perfect, so occasionally a dangerous phishing message may get past Office 365's spam filtering. In the event that this happens, OIT will protect users by removing these messages post-delivery from the mailboxes of all the people who received it. Users may be concerned when they notice these messages disappear from their mailbox, but it is important to note that this removal does not indicate any sort of compromise. The messages are removed without anyone from OIT accessing the user’s mailbox or reading their mail; it is done in bulk, and this admin activity is logged. Copies of the removed messages are preserved for a short period of time to ensure no unintended messages were removed.