Turn off Hierarchical Address Book search
Supported on: At least Windows Server 2008 R2 or Windows 7
Registry
HKCU
software\policies\microsoft\office\16.0\outlook Value name: disablehabsearch
Enabled: disablehabsearch = 1
Disabled: disablehabsearch = 0
Description
This policy setting controls entry points to search in the Hierarchical Address Book (HAB). If you enable this policy setting, all entry points to search features in the HAB will be turned off. If you disable or do not configure this policy setting, all entry points to search features in the HAB will be enabled.