“All my email address suggestions are gone since I moved to the new computer.”
That call — and its evil twin, Outlook stubbornly suggesting an address that stopped working years ago — are two of the most common classic Outlook problems we fix. Both live in the same place: Outlook’s Auto-Complete List. Here’s where it hides, and how to fix both problems.
The Suggestions Disappeared After a New PC or a New Profile
This is the number one autocomplete call we get. A fresh Outlook installation starts with an empty Auto-Complete List — the suggestions you built up over years do not appear on the new machine by themselves. If you want them back, they have to be transferred from the old device. How that works depends on your account type:
- Microsoft 365 / Exchange accounts: the Auto-Complete List is stored inside your mailbox, so it normally travels with you to a new PC on its own. If it didn’t, the usual culprit is that the first send from the new profile happened before the mailbox finished syncing. Give it time to finish, restart Outlook, and the suggestions usually return.
- POP and IMAP accounts: the list lives in a local file — look in
%LOCALAPPDATA%\Microsoft\Outlook\RoamCachefor a file starting withStream_Autocomplete_. It can be copied from the old computer to the new one, but the file name contains a profile ID that has to match the new profile, so the copy has to be renamed carefully. This is fiddly — it’s a classic “15 minutes for us remotely” job.
What the Auto-Complete List Actually Is
When you start typing in the To, Cc or Bcc field, classic Outlook shows a dropdown of matching addresses. Many people assume these suggestions come from their contacts. They don’t. The Auto-Complete List (old-timers know it as the “nickname cache” or NK2 file) is a separate list that Outlook builds from every address you have ever sent mail to — including typos, one-time replies, and addresses that stopped working years ago.
That’s why deleting someone from your contacts does not remove them from the suggestions. The two lists have nothing to do with each other.
Outlook Keeps Suggesting a Wrong or Old Address
A customer called us because her messages to a colleague kept bouncing. She typed the first few letters of his name, Outlook suggested his address, she hit Enter and Send — and the mail came back undeliverable every time. The colleague had changed companies two years ago. His old address didn’t live in her contacts; it lived in the Auto-Complete List, and it will keep coming back until you remove it from exactly that list.
Remove One Bad Address from the Suggestions
This is the fix for the bouncing-mail problem, and it takes five seconds:
- Start a new email and type the first letters of the name in the To field.
- When the dropdown appears, hover over the bad address — or move to it with the arrow keys.
- Click the X at the right end of the entry (or press the Delete key while it’s highlighted).
The entry is gone. Now send one message to the person’s correct address, and Outlook caches the right one for next time.
Why the Wrong Address Keeps Coming Back
If you delete an entry and it reappears days later, one of these is usually the reason:
- You replied to an old email. Replying to a message that was sent from the old address puts it straight back into the cache. Start a fresh email to the new address instead.
- The old address is still in a contact card. Autocomplete also offers addresses from your saved contacts. Open the contact and update the email address there too.
- A distribution list or group still contains it. Check any personal groups the person belongs to.
Clear the Entire Auto-Complete List
If the list is full of years of junk, you can wipe it clean. In classic Outlook:
- File → Options → Mail
- Scroll to the Send messages section
- Click Empty Auto-Complete List, then confirm.
The same section has the checkbox “Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines” — untick it if you’d rather Outlook made no suggestions at all.
A heads-up before you click: emptying the list means Outlook forgets every address you’ve ever typed, and will only relearn them as you send new mail. If you rely on suggestions instead of saved contacts, add the important people to your contacts first.
What About the New Outlook?
Microsoft is replacing classic Outlook with the web-based “new Outlook,” and autocomplete is one of the things that behaves differently there. The new app builds its suggestions from your contacts and the server’s own list of people you interact with — there is no local cache file, and the classic Empty Auto-Complete List button doesn’t exist. You can still remove a single wrong suggestion the same way: hover over it in the dropdown and click the X.
If your Outlook suddenly looks different and settings aren’t where this article says they are, you’ve probably been switched to new Outlook — we’ve written about the problems that causes with Intermedia hosted Exchange accounts and with the “you are not responding to the latest message” warning.
Still Fighting With It?
Autocomplete problems are quick fixes for us: we connect remotely, billed by the minute, and most cache cleanups are done in well under half an hour. Call or text (571) 604-5679, request help online, or see our services and pricing.