My Microsoft account says it doesn't exist but I'm signed in to Windows and Microsoft Store.

The email address used on the PC and Microsoft Store must be checked first to confirm whether it is still a Microsoft account, and whether it may have been closed.

1. Confirm whether the email is still a Microsoft account
   1. Go to the Microsoft account sign-in page at https://account.microsoft.com.
   2. Enter the Gmail address that is shown as the account on the signed‑in PC.
   3. If the message "We couldn't find an account with that username" or "That Microsoft account doesn't exist" appears, then that email address is not currently a Microsoft account. In that case:
      • Carefully check spelling of the name and domain (for example, rachel vs rachael, .com vs .co.uk).
      • The account may have been closed; see the guidance under "The account may have been closed" in the referenced article.
   4. If a password prompt appears instead, then the email is still a Microsoft account and the password can be reset using Forgot password?.
2. If the username and password have stopped working
   1. Use the recovery flow at Recover your account.
   2. Enter the email address, phone number, or Skype name used to sign in.
   3. Follow the prompts to receive a security code and set a new password.
   4. If the email is not recognized, and there is another alias or phone number on the account, try that instead.
3. If the account is reported as not existing
   • If the sign-in page and the recovery page both report that the Microsoft account does not exist, then the email address is not currently an active Microsoft account. The documentation indicates that:
     • If an account has not been signed into for more than two years, it may have been deleted and can no longer be reopened.
     • When the message "The Microsoft account you've entered does not exist" appears on the recovery form, the next step is to verify spelling and then follow the guidance in "My username and password have stopped working".
   • If the username is still not recognized after these checks, the documented path is to contact support using the Contact support option in "My username and password have stopped working" and explain that the username has stopped working.
4. Using the signed‑in PC The provided documentation does not describe any special or alternative verification process that uses an already signed‑in Windows or Microsoft Store session to re‑activate or recreate a Microsoft account that is reported as non‑existent. All recovery and verification flows rely on the standard sign‑in, password reset, and account recovery tools:
   • Sign-in Helper
   • Recover your account
   • Account recovery form

If the email is confirmed not to be a Microsoft account (or the account has been deleted), a new Microsoft account must be created with a valid email address, and that new account used to sign in going forward.

References:

• I can't sign in to my Microsoft account
• How to check if your email address is a Microsoft account
• My username and password have stopped working
• Help with the Microsoft account recovery form
• Check products or services where you used your Microsoft account
• I can't sign in to my Microsoft account – Frequently asked questions