How to Fix Outlook Auto-Complete List Not Suggesting Email Addresses in Microsoft 365

Summary

This guide helps you troubleshoot and resolve: How to Fix Outlook Auto-Complete List Not Suggesting Email Addresses in Microsoft 365. Follow the steps below to fix the issue.

Common Causes

Microsoft Outlook uses an Auto-Complete list to suggest email addresses as you type in the To, Cc, and Bcc fields. This list is stored locally in your Outlook profile and is separate from your address book. If suggestions stop appearing, the cache may be disabled, corrupted, or Outlook may be running in offline mode. Follow the steps below to restore Auto-Complete suggestions in Microsoft 365 Outlook.

Quick Fix Steps

1. Confirm Outlook is online. Look at the status bar at the bottom of the window. If it shows Working Offline, select the Send/Receive tab and choose Work Offline to reconnect.
2. Compose a new email and send a message to a recipient. This forces Outlook to create a fresh Auto-Complete entry.
3. Restart Outlook and check if suggestions reappear when typing in the To field.

Detailed Instructions

Check Auto-Complete is enabled

1. Open Outlook and select File > Options.
2. In the left pane, choose Mail.
3. Scroll to the Send messages section.
4. Ensure the checkbox Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines is ticked.
5. Select OK and restart Outlook.

Empty the Auto-Complete list

1. Open Outlook and select File > Options > Mail.
2. Under Send messages, select Empty Auto-Complete List.
3. When prompted, select Yes to confirm.
4. Select OK, then close and reopen Outlook.
5. Send a new email to begin rebuilding the list.

Clear the Auto-Complete cache file

If enabling or emptying the list does not help, you can delete the local cache file so Outlook recreates it.

1. Close Outlook completely.
2. Press Windows key + R to open the Run dialog.
3. Type %appdata%\Microsoft\Outlook and select OK.
4. Locate the file ending in .nk2 for older Outlook versions, or the Stream_AutoComplete file for newer Microsoft 365 versions.
5. Rename the file by adding .old to the end of the filename.
6. Restart Outlook. A new cache file will be created automatically.

Repair Microsoft 365 Apps

1. Close all Office applications.
2. Open Control Panel and select Programs and Features.
3. Find Microsoft 365 or Microsoft Office in the list.
4. Select Change > Quick Repair > Repair.
5. Restart your computer when the repair finishes.

Troubleshooting

Auto-Complete works in Outlook on the web but not desktop

The desktop Auto-Complete list does not sync with Outlook on the web. Addresses suggested in Outlook on the web are stored separately and will not appear in the desktop application until you email those contacts from Outlook for Windows or Mac.

Suggestions appear but are outdated

Outlook prioritises recently used addresses. If an email address has changed, select the incorrect suggestion from the drop-down list and press Delete to remove it, then type the correct address and send a message to save the new entry.

Using Outlook for Mac

1. Open Outlook and select Outlook > Settings > Compose.
2. Ensure Autocomplete recent addresses is enabled.
3. To clear the list, quit Outlook, open Finder, and select Go > Go to Folder.
4. Enter ~/Library/Containers/com.microsoft.Outlook/Data/Library/Preferences/ and locate the Auto-Complete plist file.
5. Move the file to the Trash and restart Outlook.

If Auto-Complete suggestions still do not appear after following these steps, Open a Ticket with 220 Internet Services support.

Related guides:

• Setting Up an Email Account in Outlook (POP/IMAP/Exchange)
• Managing Email Signatures in Outlook
• Troubleshooting Outlook Send/Receive Errors
• Backing Up and Restoring Outlook Data Files (.pst/.ost)
• Organizing Emails with Rules and Alerts in Outlook
• Using Outlook Calendar and Scheduling Meetings

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