All versions of
Outlook support Autoresolve. Also known as automatic name checking, this
feature allows you to type a name, or even just the first few letters, and the
name resolves a few seconds after you tab out of the field. When one match is
found, the name has a solid underline. When more than one possible match exist
you’ll see a red wavy underline. Right click on it to choose an address. When
more than one match exists for a name you’ve used before, Outlook resolves to
the last name used and uses a green dotted line to alert you that other
possibilities exist. Right click to see the other addresses. When Name checking
is disabled in Tools, Options, Email Options, Advanced Options it won’t do it
as you type the names in but it will check and resolve them when you hit Send.
You can force an autoresolve at anytime using Ctrl+K.
To resolve this issue create a new mail profile.