ISSUE: When creating a new email, typing any letter into the To: field used to produce a scrollable list of cached addresses, both inside and outside the company. Office was patched some time ago (looks like late 2017 from forums), and now the same steps produce a limited, non-scrollable list of only five "Recent People" choices.
If the user wants the old scrollbar version back, this step has been tested and worked:
1. Go to HKCU\Software\Microsoft\Office\16.0\Outlook\Options
2. Right-click the Options folder, then create a new DWORD called DisableAutoCompleteUpdate
3. Modify that index's value from 0 to 1
4. Close and reopen Outlook and test with user