Thanks for reaching out to Microsoft Q&A Forum. I understand that you are unable to sign in to your Microsoft account because parental rights are still applied even though you are already 18 years old.
Please make sure you have already tried the steps suggested by Q&A Assist. In addition, please try the following steps:
1, Sign in to https://account.microsoft.com/family using the Microsoft account that is currently set as your parent or organizer.
- Select your account from the family list
- Choose Remove from family or turn off family features
2, If the parent or organizer account is no longer accessible, go to https://account.microsoft.com.
- Sign in with your affected Microsoft account
- Select Your info to verify the birth date is set to reflect that you are over 18
3, Go to https://account.microsoft.com/family.
- Check whether your account still appears under a family group
- If it does, attempt to leave the family group from your account
4, Sign out of all devices and browsers, then sign in again using your Microsoft account.
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