Personal email is linked to a random email when typed in

In Outlook and Outlook.com, this behavior is caused by stored suggestions (autocomplete) and/or a contact entry that links the display name to a different underlying email address.

Because the issue follows the account across all browsers, apps, and devices, the incorrect mapping is stored in the mailbox (as a contact or cached suggestion), not in a specific device.

To fix it, remove the bad entry everywhere it can be stored:

1. When composing a new email, start typing the personal email address in the To field.
2. When the wrong suggestion appears (showing the random address in angle brackets), hover over or highlight that suggestion and delete it (for example, by selecting X, Remove, or using Delete on the highlighted suggestion, depending on the Outlook client).
3. In Outlook/Outlook.com, open People/Contacts and search for both:
   • The personal email address, and
   • The random @outlook.com address. If any contact exists that shows the personal address as the display name and the random address as the actual email, delete that contact.
4. If using Outlook mobile (Android/iOS), also check the app’s contacts:
   • Open Settings > Accounts and confirm only the intended accounts are present.
   • If an unwanted account is present, remove it using Remove Account.

If the wrong address is associated with a Microsoft account alias, verify aliases for the Outlook.com account and remove any unwanted alias that might be causing messages to send from the random Outlook address. Be aware that removing an alias can be permanent and should only be done if it is not needed for sign-in or recovery.

After removing the autocomplete entry and any incorrect contact, new messages should no longer replace the personal email with the random address.

References:

• Why am I seeing a work contact show up as a suggestion when writing from my personal email address?
• How do I remove my email account?
• Email sent from wrong address