When Outlook AutoComplete stops working, every email starts with manual typing, copied addresses, and extra trips to the address book. The fix depends on whether your suggestions come from classic Outlook's AutoComplete list, saved contacts, or Microsoft account suggested contacts.
Start with the setting that controls recipient suggestions, then clear bad entries, add missing contacts, and repair Outlook only after the faster fixes are done. All steps below use current Microsoft-supported methods.
Check the AutoComplete setting in classic Outlook
Classic Outlook for Windows has a setting that controls name suggestions in the recipient fields. Open Outlook, then go to File, Options, Mail, and Send messages.
Check Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines, then select OK. This applies to classic Outlook for Microsoft 365, Outlook 2024, Outlook LTSC 2021, Outlook 2019, and Outlook 2016.
For Outlook for Microsoft 365 Version 2202 or later connected to Exchange Online, Microsoft Search powers compose suggestions, and this setting still applies. Keep the box checked before moving to the next fix.
Clear the AutoComplete list and let Outlook rebuild it
This fixes a damaged or stale classic Outlook AutoComplete list, especially with POP, IMAP, or Exchange On-Premises nickname-cache issues.
Open Outlook.
Select File, then choose Options.
Select Mail.
Under Send Messages, select Empty Auto-Complete List.
When Outlook asks you to confirm, select Yes.
Send test emails to rebuild the suggestion list.
Remove a wrong or stuck recipient
Open a new email message in classic Outlook.
Type the first few characters of the bad suggestion in the To, Cc, or Bcc field.
When the entry appears, hover over it until it is highlighted.
Select the X icon, or press the DELETE key.
For Exchange Online accounts, the X can appear and the suggestion can return because Microsoft Search supplies it.
Tip: reset suggested contacts from your Microsoft account privacy settings when deleted Exchange Online suggestions keep returning.
Reset Microsoft Search suggested contacts
Some Outlook suggestions are not stored in the old local AutoComplete cache. For Exchange Online and Microsoft account suggestions, use the privacy controls that manage suggested recipients across Outlook and other Microsoft 365 surfaces.
For a work or school account, go to Settings & Privacy at myaccount.microsoft.com, open the Privacy tab, choose Data options, then open Manage contact suggestions and discovery. Under Discovered contacts, turn Discovered contacts off or select Clear data.
For a personal Microsoft account, go to Privacy at account.microsoft.com, open Empower your productivity, then use People suggestions and turn the toggle off. Use this route when old cache-clearing fixes leave the same names in Outlook suggestions.
Use the address book when new Outlook will not suggest a name
This method applies when new Outlook does not show the recipient you need while you type. It also works when you want to choose a name from a contact list directly.
Create a new email or reply to an existing one.
Select Address book in the ribbon, or select To, Cc, or Bcc in the message address area.
In Add recipients, choose the contact list you want to search.
Use Search this list of contacts to type the person's name or email address.
Select the recipient, then select Save.
For global address lists with more than 500 contacts, start typing a first name, last name, or email address before Outlook searches the list.
Add the person as a saved contact
Outlook suggests people from saved contacts, so adding a missing recipient gives Outlook another source to use. This works in new Outlook, classic Outlook, Outlook on the web, and current Outlook desktop versions listed by Microsoft.
Open People, select New contact, enter the person's details, then select Save or Create. From an email, open the message, select the sender or recipient name, choose More options, select Add to contacts, enter the details, and select Save or Create.
On some work accounts, an organization address book policy blocks internal recipients from suggestions. Add the internal address as a personal contact; when the policy is unnecessary, an Exchange Online admin removes the address book policy assigned to the sender.
Test Outlook without add-ins
Use Safe Mode to check whether an add-in is interfering with Outlook behavior:
- 1.Right-click Start and select Run.
- 2.Type Outlook.exe /safe.
- 3.Select OK.
- 4.If Windows cannot find Outlook, use the full path to Outlook.exe.
- 5.If AutoComplete works in Safe Mode, open Outlook normally and turn off the problem COM add-in. Go to File, Options, Add-ins, select COM Add-ins in the Manage box, then select Go. Clear the check boxes, select OK, restart Outlook, and re-enable the add-ins one at a time until AutoComplete breaks again. Skip File and Manage Add-ins here: that opens Outlook on the web and only covers web add-ins, not the COM add-ins Safe Mode just turned off.
Create a fresh Outlook profile
The most common reason to try a new profile here is a damaged local Outlook profile after the basic AutoComplete fixes have failed.
Hold Shift while starting Outlook.
In the profile picker, select Options.
Select New, type a name for the new Outlook profile, then select OK.
Add your email account to the new profile and test AutoComplete again.
You can also open the profile picker by right-clicking Start, choosing Run, typing Outlook.exe /profiles, and pressing Enter. Another path is File, Account Settings, Change Profile, then restart Outlook.
Update or repair Outlook
When Outlook itself is malfunctioning, update Microsoft 365 or Office before reinstalling anything. Open any Microsoft 365 app, go to File, Account, or Office Account in classic Outlook, then choose Update Options and Update Now.
If updates are disabled, choose Enable Updates first. Close the You're up to date! or Updates were installed window when the update finishes.
For a deeper repair on Windows 11, right-click Start, open Installed apps, select your Microsoft 365 or Office product, choose the ellipses, then select Modify. On Windows 10, right-click Start, open Apps and Features, select Microsoft 365 or Office, then choose Modify. What appears next depends on your install type. Click-to-Run installs, the most common kind, show How would you like to repair your Office Programs: choose Online Repair, then Repair. MSI-based installs show Change your installation instead: choose Repair, then Continue.
If this method fails, reinstall the current Outlook app from Microsoft's official Outlook download page or Microsoft 365 install page.
Skip outdated AutoComplete fixes
Older Outlook guides often recommend renaming the RoamCache folder or disabling the old Outlook Change Notifier add-in from an iTunes-era Outlook 2010 setup. Microsoft documents those as legacy Outlook 2010 scenarios, not current general fixes for Outlook for Microsoft 365 or Outlook 2024.
The current replacement depends on your account type. For POP, IMAP, and Exchange On-Premises accounts, use the Outlook AutoComplete setting, clear the AutoComplete list from Outlook, and remove bad entries with the X or DELETE key. For Exchange Online accounts, Microsoft's open known-issue notice, last updated June 17, 2026, says removed suggestions can come back and that turning AutoComplete off and on or clearing the AutoComplete cache does not affect that behavior, so reset Microsoft Search suggested contacts from the Microsoft account privacy controls instead.
If these current methods fail, update Outlook, create a fresh Outlook profile, or repair Microsoft 365 or Office instead of using Outlook 2010 cache workarounds.
Frequently Asked Questions
Why does Outlook keep bringing back a deleted AutoComplete suggestion?
For Exchange Online accounts, Microsoft Search can supply recipient suggestions after you remove an entry with the X. Reset or turn off suggested contacts from your Microsoft account privacy settings.
Does clearing the AutoComplete list delete my contacts?
No. The Microsoft steps clear the classic Outlook AutoComplete list. Saved contacts are managed separately in People or Contacts.
Why do internal coworkers not appear in AutoComplete?
In some Exchange Online organizations, an address book policy blocks internal-recipient suggestions. Add the person as a personal contact, or ask your admin to review the policy.
Is the RoamCache folder fix still recommended?
No. Microsoft documents that method for Outlook 2010. Use the current Outlook settings, Microsoft account suggested-contact controls, profile repair, update, or Office repair steps instead.