Malicious Rules - Hotmail Hard Reset

I understand why you are looking for a complete reset here, David Azariah.

If malicious rules are reappearing after you delete them, it suggests that the account or something connected may still have unauthorized access. Unfortunately, there's no such thing as a "hard reset" for Outlook to bring all configuration back to defaults while preserving the account. Instead, consider cutting off every remaining access path:

1. Run a full malware scan on devices the account used to sign in.
2. Visit https://account.microsoft.com/security > click Manage how I sign in
   1. Scroll down > click Sign out everywhere (optional: Reset Windows Hello...)
   2. Generate a new recovery code in case the attacker previously saved it.
3. Back to Security, check the Recent activity page carefully, especially entries around the time of the rule creation.
4. Open Outlook again, check Settings > Mail and make sure nothing suspicious has been enabled:
   1. Forwarding and IMAP
   2. Automatic replies
   3. Connected accounts

Look for third-party mail clients/devices that still have the mailbox configured (e.g. classic Outlook, Apple Mail, Thunderbird, mobile mail applications, or another device). Temporarily removing the Outlook account from every mail client, then delete the malicious rule again.

That said, if new malicious rules continue to appear after the account has been secured and all sessions have been terminated, this goes beyond what we can investigate on Microsoft Q&A. This is just a community support forum, and contributors here have no access to Outlook's account/session logs or backend mailbox configuration.

In that situation, consider trying the Microsoft's hacked or compromised account recovery process. It can detect your issue and offer appropriate recovery steps. Depending on the case, it may offer you an option to speak with an agent. For now, avoid using the mailbox normally or sending sensitive information from it until the unauthorized rules stop appearing.