You deleted a pile of old names from Suggested Contacts, yet Outlook keeps suggesting every one of them. Or the reverse: your suggestions work perfectly but a mysterious folder keeps filling with people. Both mysteries have the same answer - Outlook keeps two separate name systems, and only one of them drives autofill.
Few Outlook confusions waste as much time as this one. Suggested Contacts is a visible folder Outlook fills automatically. AutoComplete is an invisible cache that powers the To-field drop-down. They grow from the same activity, hold similar names, and are not connected - deleting from one never cleans the other. This page separates them properly.
Buried in your folders list (often under Contacts, or visible in the People view) sits a folder called Suggested Contacts. Classic Outlook maintains it automatically: when you receive mail from, or send mail to, someone who is not already in your Contacts, Outlook may quietly save their name and address there. It is a real contacts folder - you can open it, browse it, and delete entries from it. Many users discover it by accident and assume it powers the To-field drop-down. It does not.
The To-field suggestions come from the Stream_Autocomplete cache file, a private list Outlook maintains for speed. It overlaps heavily with Suggested Contacts - both grow from the same email traffic - but they are written separately and never synchronised back into each other. Think of them as two notebooks kept by two different clerks who watch the same desk: the names look alike, the books are not the same book.
Armed with a spring-cleaning mood, a user deletes fifty stale entries from Suggested Contacts, opens a new email - and the same stale names are still suggested. Frustration follows, and sometimes a worse cleanup attempt with the Empty List button. The correct tools, matched to the job:
Honestly: not directly, and not with a button. There is no built-in "import Suggested Contacts into AutoComplete" command. But the folder is still useful after a list loss - it is a browsable record of the people you actually deal with, so you can re-email your regulars from it (each send re-teaches AutoComplete) and promote the important ones into real Contacts with a right-click. Treat it as the backup memory you browse, while AutoComplete remains the memory Outlook types from.
The video opens both systems on screen - the Suggested Contacts folder and the suggestion drop-down - and shows a delete in each, so you can see which one changes what.
▶️ Watch Full VideoBecause suggestions come from the AutoComplete cache, a separate store that Suggested Contacts does not feed or control. Deleting the folder entry cleaned your address book only. To stop the suggestion itself, type the name in the To field and click the X on that suggestion row - that edits the cache directly.
Suggested Contacts behaviour is limited in classic Outlook - the folder is created and maintained automatically for accounts in the profile, and there is no prominent off switch for it in Options. The practical approach is to ignore the folder or periodically clear it; autofill is independent and keeps working either way, since it reads its own cache file.
Clean the AutoComplete suggestion - that is the list your fingers actually pick from at speed. Then also delete or correct the entry in Contacts or Suggested Contacts so the wrong address stops being offered through Search People as well. Doing both takes a minute and closes both doors the mistake walks through.