Organizing and accessing contact information in Outlook.com
I understand how frustrating it is to add several addresses and then find that the changes have disappeared.
Please open Outlook in an InPrivate/Incognito window, sign in, and try adding one test address to the same contact list. If the address saves there, clear the cookies and cached site data for Outlook in your regular browser, then sign in again.
If the issue continues in the private window, please create a temporary contact list and add a few test addresses:
- If the temporary list saves correctly, the original contact list may be affected. You can use the new list and gradually add the members again.
- If neither list saves, try another supported browser to determine whether the behavior is browser-specific.
Also, please confirm whether you are using Outlook.com, new Outlook for Windows, classic Outlook, or Outlook for Mac, and whether this is a personal or work/school account. This will help identify the next appropriate troubleshooting step.
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