mrt asked to get my Microsoft edge username and password whilst a full scan was happening

It sounds like you encountered a potentially concerning situation with the MRT.exe process attempting to access your Microsoft Edge username and password. MRT.exe, or the Microsoft Windows Malicious Software Removal Tool, is a legitimate Microsoft tool designed to remove specific malware from Windows systems. However, if it is attempting to access sensitive information like usernames and passwords, it could indicate unusual behavior or a possible security issue.

Since you mentioned that Norton blocked the request and your scan results showed no infections, it is a good sign that your system is likely secure. However, it’s always wise to stay vigilant. Here are some steps you can take to ensure your system's safety:

1. Run a Full Scan: Use your antivirus software (like Norton) to perform a full system scan to check for any hidden threats.
2. Check for Unusual Activity: Monitor your accounts for any unauthorized access or unusual activity.
3. Keep Software Updated: Ensure that your operating system and all security software are up to date to protect against vulnerabilities.
4. Change Passwords: If you feel uncertain, consider changing your Microsoft Edge and other important passwords.
5. Report Suspicious Activity: If you continue to see suspicious behavior, consider reporting it to Microsoft or your antivirus provider.

If you have any further concerns or notice more unusual behavior, it might be beneficial to consult with a professional for a more thorough investigation.

References:

• Tech support scams
• Protect against PUA with Windows Defender Antivirus