How to Clear the AutoComplete Cache in Outlook

To clear every saved recipient suggestion in classic Outlook for Windows, select File > Options > Mail > Empty Auto-Complete List, then confirm. New Outlook and Outlook on the web generally let you remove suggestions one at a time instead. Clearing the cache removes remembered address suggestions; it does not delete contacts or messages.

What You’ll Need

Access to the Outlook account whose suggestions you want to clear.
For the full-list reset, classic Outlook for Windows. The command is not available in every Outlook version.
A minute to check your version and confirm the change. You do not need administrator access or to download a cleanup tool.

Outlook’s AutoComplete cache (also called the recipient suggestion list) is the set of addresses Outlook offers as you type in the To, Cc, or Bcc field. It can include people you emailed once, old addresses, and addresses that are no longer correct. The list is separate from your address book, so clearing it should not remove saved contacts.

Step-by-Step

Check which Outlook you are using. The full clear-list command described below is for classic Outlook for Windows, the desktop app with the traditional File tab. New Outlook has a different interface and a New Outlook switch in some installations. Outlook on the web opens in a browser. On a Mac, Outlook has its own Previous Recipients list. Use the steps for your version rather than looking for a Windows-only button that is not there.
In classic Outlook for Windows, open the Mail options. Select File in the upper-left corner, then choose Options. In the Outlook Options window, select Mail in the left-hand list. If File > Options is missing, you are likely using new Outlook or another Outlook version; skip to the version-specific guidance below.
Find the AutoComplete control. In the Mail settings, scroll to the Send messages section. Select Empty Auto-Complete List. The button is specifically for the saved recipient suggestions; it does not clear your mailbox or address book.
Confirm that you want to empty the list. Outlook displays a confirmation prompt because the action removes the saved suggestions. Choose Yes to proceed. If you choose No or cancel, the existing entries remain.
Close the options window and test a recipient field. Select OK to close Outlook Options. Start a new email and type a few letters of a recipient you previously saw suggested. The old cached suggestion should no longer appear. Do not send a test message unless you intend to send it; you can close the draft afterward.
In new Outlook or Outlook on the web, remove suggestions individually. Start a new message and type enough of the person’s name or address to show the unwanted suggestion. Point to the suggestion or select it, then use the X or remove control beside that entry if shown. Confirm if prompted. Repeat for each unwanted recipient. Interface details can vary by account and rollout, and there may not be a bulk-clear command in these versions.
On Outlook for Mac, check Previous Recipients. In Outlook, open the Window menu and choose Previous Recipients, if that command is available in your version. Find the address, select it, and use the remove or delete control in that window. Repeat for other entries. In some versions, you can also remove a suggestion from a new message by selecting its remove control. This list is distinct from your Contacts.

After clearing or removing entries, allow Outlook to finish syncing if you use multiple devices. A suggestion can come from a different source, such as a saved contact, a company directory, or another device’s account data. If the address returns, use the troubleshooting section to identify which source is supplying it.

Common Mistakes

Confusing classic and new Outlook. The File > Options > Mail route belongs to classic Outlook for Windows. Searching for that route in new Outlook or Outlook on the web can waste time because those interfaces do not have the same Options window. Remove suggestions from the compose field in those versions instead.
Expecting the address book to be erased. Empty Auto-Complete List clears remembered recipient suggestions, not entries in Contacts, a company directory, or a mailbox. If an address is saved as a contact, it may still appear when you search for people.
Removing only one entry when you meant to clear all. Clicking the X beside a suggestion removes that recipient, not the entire list. In classic Outlook, use Empty Auto-Complete List for the full reset. In versions without that command, repeat the individual removal process for each address you want gone.
Deleting messages or contacts as a workaround. Deleting an email conversation does not reliably clear a recipient suggestion. Deleting a contact is a separate action and can remove useful contact information without fixing a suggestion supplied by another source.
Using old cleanup instructions or tools. Instructions that tell you to delete an NK2 file or edit the Windows registry may apply to older Outlook releases, not current Microsoft 365 Outlook. Avoid third-party cache cleaners and registry changes; they are unnecessary for the supported steps here and can cause other problems.

Tips

Remove one bad suggestion before clearing everything. If only one address is outdated, use its X or remove control in the suggestion list. That preserves useful suggestions for other recipients.
Check the full address before sending. Similar names can have multiple addresses, especially after a colleague changes jobs or an organization changes domains. Select the correct suggestion deliberately, or type the complete address and verify it before sending.
Keep important people in Contacts. AutoComplete is a convenience list, not a reliable address book. Save frequently used recipients as contacts so you can find them again even after clearing suggestions.
Remember that accounts and devices can behave differently. A suggestion list may be associated with an Outlook profile or account, while contacts and organization directories can sync separately. Removing an entry in one place may not remove a matching contact or directory result elsewhere.
Use a draft to check the result safely. Open a new message, test the address field, and close the unsent draft. This confirms what Outlook suggests without risking an accidental email.

Troubleshooting

The Empty Auto-Complete List button is missing. Confirm that you are in classic Outlook for Windows and have opened File > Options > Mail. If you are in new Outlook, Outlook on the web, or Outlook for Mac, use the corresponding individual-removal method. If your workplace manages Outlook settings, some controls may also be restricted by organizational policy.

The address still appears after you cleared the list. Check whether the result is marked or presented as a contact or directory match rather than a remembered suggestion. Search Contacts or People for the address, and check your organization’s directory if you use a work account. If it is a contact you no longer want, edit or delete that contact separately, taking care not to remove a shared or organization-managed record.

The suggestion returns after restarting Outlook. First check whether the person is saved as a contact, then try removing the entry again from the same account and device where it reappears. If you use multiple Outlook profiles or accounts, make sure you cleared the correct one. For a work or school account, a directory result or organizational service may continue to offer the address; clearing the local recipient cache cannot remove a directory entry.

You removed a suggestion but still see a similar name. There may be more than one address for that person, or different people may share a name. Type more characters to distinguish the entries, inspect the full email address, and remove each unwanted address separately. Avoid deleting a contact until you have confirmed it is the source of the unwanted result.

Outlook behaves differently on another computer. Check the Outlook version, account, and profile on that computer. The available removal controls differ across classic Outlook, new Outlook, Mac, and the web, and synced contacts can remain visible even when a cached suggestion has been removed. Apply the relevant steps on the device where the suggestion appears.

The interface does not match these directions. Microsoft updates Outlook interfaces over time, and work or school accounts can have different features enabled. Search the app’s Settings for recipient or suggestion controls, or use the X beside a displayed suggestion. If neither option is available, check with your organization’s Microsoft 365 administrator rather than changing registry settings or deleting Outlook data files.

Frequently Asked Questions

Will clearing AutoComplete delete my contacts?
No. In classic Outlook, Empty Auto-Complete List removes cached recipient suggestions. Contacts and directory entries are separate and are not deleted by that command.

Can I clear just one address?
Yes. Show the suggestion in the To, Cc, or Bcc field and select its X or remove control. In classic Outlook, you can also clear the entire list from File > Options > Mail if you want to remove all cached suggestions.

Can I clear all suggestions in new Outlook?
New Outlook does not always provide the same bulk-clear control as classic Outlook. Remove unwanted recipients one at a time from the suggestions shown while composing a message. Available controls can vary as Microsoft updates the app.

Does clearing the cache recall emails I already sent?
No. Clearing recipient suggestions does not delete, recall, or alter sent messages. It only affects addresses Outlook offers as you type.

Why does an old work address keep appearing?
It may be saved as a contact or supplied by your organization’s directory rather than by the AutoComplete cache. Check the full address and its source; ask your Microsoft 365 administrator about organization-managed directory information.

Do I need to clear AutoComplete regularly?
Usually not. Clear it when suggestions are cluttered, inaccurate, or contain addresses you no longer want offered. For a single typo or outdated address, removing just that entry is less disruptive.

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