Remove the recipient’s email address from your Auto-Complete list
You might have an invalid entry in your Auto-Complete list (also known as the nickname cache) for the recipient. For example, the recipient might have been moved from an on-premises Exchange organization to Exchange Online, or vice-versa. Although the recipient’s email address is the same, other internal identifiers for the recipient might have changed, thus breaking your cached entry for the recipient.
Fix your Auto-Complete list entries in Outlook
To remove invalid recipients or all recipients from your Auto-Complete list in Outlook 2010 later, see Manage suggested recipients in the To, Cc, and Bcc boxes with Auto-Complete.
Fix your Auto-Complete list entries in Outlook on the web
To remove recipients from your Auto-Complete list in Outlook on the web (formerly known as Outlook Web App), do one of the following procedures:
Remove a single recipient from your Outlook on the web Auto-Complete list
- In Outlook on the web, click New mail.
- Start typing the recipient’s name or email address in the To field until the recipient appears in the drop-down list.
- Use the Down Arrow and Up Arrow keys to select the recipient, and then press the Delete key.
Remove all recipients from your Outlook on the web Auto-Complete list**
You can only clear your Auto-Complete list in the light version of Outlook on the web. To open your mailbox in the light version of Outlook on the web, do either of the following steps:
- Open the mailbox in an older web browser that only supports the light version of Outlook on the web (for example, Internet Explorer 9).
- Configure your Outlook on the web settings to only use the light version of Outlook on the web (the change takes effect the next time you open the mailbox):
- In Outlook on the web, click Settings .
- In the Search all settings box, type light and select Outlook on the web version in the results.
- In the page that opens, select Use the light version of Outlook on the web, and then click Save.
- Log off, close your web browser, and open the mailbox again in Outlook on the web.
After you open your mailbox in the light version of Outlook on the web, do the following steps to clear all entries from your Auto-Complete list:
- Choose Options and verify that Messaging is selected.
- In the E-Mail Name Resolution section, click Clear Most Recent Recipients list, and then click OK in the confirmation dialog box.
- While you’re still in Options, to return your mailbox to the full version of Outlook on the web, go to Outlook version, clear the check box for Use the light version, and then click Save.
- Log off and close your web browser. The next time you open your mailbox in a supported web browser, you’ll use the full version of Outlook on the web.