How to Fix “Outlook AutoComplete Not Working” Isssue?

Jenny Lowrence | February 27th, 2026 | Outlook Errors

Are you wondering about how to fix Outlook AutoComplete not working issue? Well, fear not! In this guide, we will explain several techniques to help you resolve the AutoComplete not working in Outlook error. So, stay tuned with us to know the step-by-step procedure.

Before moving ahead, let’s take a moment to understand Outlook AutoComplete and the reason it’s not working.

What is Outlook AutoComplete?

The Outlook AutoComplete is a feature in Microsoft Outlook that automatically suggests email addresses as you type in the To, Cc, or Bcc fields while composing a message. Each time you send an email, Outlook adds the recipient’s address to the AutoComplete list. Next time, when you start typing a name or email address, Outlook displays matching suggestions from this saved list.

Why is Outlook AutoComplete Not Working?

Here are some common reasons for not showing Outlook AutoComplete list:

  • If the AutoComplete feature is disabled, then Outlook AutoComplete not work.
  • Sometimes, AutoComplete cache file becomes corrupted. It may stop Outlook from showing suggested email addresses.
  • If the Outlook profile is corrupted, then you may face Outlook AutoComplete not working issue.
  • Incompatible add-ins may stop Outlook to showing the AutoComplete list.
  • If the Outlook is not up-to-date, then it may also cause of this issue.
  • An oversized or corrupted OST file can also cause the Outlook AutoComplete list not showing.

How to Fix Outlook AutoComplete Not Working Issue?

Here are some tried and tested solutions to solve AutoComplete not working in Outlook error.

1. Check AutoComplete Option is Enabled

Sometimes the AutoComplete feature is turned off then check this feature and enabled it.

  1. Open Outlook on your system.
  2. Go to File >> Options.
  3. Now, click on Mail, scroll down and locate the send messages section.
  4. Check the box Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines.
  5. Click Empty Auto-Complete List and click on Yes to confirm.
  6. Click on OK to apply the new changes.

2. Update Outlook

If your Outlook is outdated, then the AutoComplete feature may stop working.

  1. Open Outlook on your system.
  2. Click on File tab and select Office Account option.
  3. Click on Update options and choose Update Now.

Wait some tome to complete the update and restart computer. After that, open Outlook and check AutoComplete list is showing or not.

3. Regenerate the Outlook AutoComplete List Again

  1. Open Outlook and go to File tab.
  2. Choose Options from menu.
  3. Go to Send Messages settings under Mail.
  4. Select Empty AutoComplete List to delete the current suggestions.
  5. Click OK to save changes.
  6. Compose a new email and type the email address and then send it.
  7. Outlook will automatically add the email addresses to the AutoComplete list as you send emails.

4. Generate a New RoamCache

  1. Open MS Outlook on your system.
  2. Go to File >> Account Settings.
  3. Select your email account and click on Change.
  4. Click on More Settings and go to Advanced tab.
  5. Uncheck the Use Cached Exchnage Mode option and press Next.
  6. Open the Run command and type %LocalAppData%\Microsoft\Outlook and press Enter.
  7. Right-click on RoamCache folder and click on Rename option.
  8. Enter a new name. After that, relaunch Outlook, and it will create a fresh RoamCache folder.
  9. Compose a new email to check AutoComplete is working or not.

5. Create a New Outlook Profile

  1. First of all, close Outlook and open Control Panel.
  2. Click on User Accounts >> Mail >> Show Profiles >> Add.
  3. Enter your new profile name and press OK.
  4. Follow the instructions and tap on Finish.
  5. Set the new profile as default and press OK.

6. Disable Conflicting Add-ins

  1. Open Outlook in Safe Mode.
  2. Go to File >> Options >> Add-ins.
  3. Press Go button next to COM add-ins.
  4. Deselect each add-in and click OK.

After that, restart Outlook and check the AutoComplete is working or not.

7. Rebuild the OST File

Corrupted or inaccessible Outlook data files can also cause for Outlook AutoComplete not working. You can rebuild the OST file to solve it.

  1. Open Control Panel.
  2. Click on Mail and choose Data Files.
  3. Select the email account and copy the file path of the data file.
  4. Open the path in File Explorer and rename or delete the file.
  5. After that, restart Outlook, it will automatically create new data file.

If the Outlook fails to recreate an OST file due to any issues, like Exchange server or profile corruption, converting it into PST format is the best approach. Advik OST to PST Converter offers a secure way to recover data from corrupted OST files. After converting, you can import the converted file into Outlook.

Final Words

In this post, we have discussed how to fix Outlook AutoComplete not working error. Here, we shared the major reasons that inform us why the AutoComplete list is not showing in Outlook. We provided the best solutions to solve it. Follow the above suggested methods to get AutoComplete back in working mode.