Microsoft 365 Account Hacked What to Do Immediately

| September 29, 2026

Microsoft 365 Account Hacked What to Do Immediately

Quick answer: read this entire blog post and if you need my help, use the form below to get in contact. Take note: Always have a second global admin account to back you up!

How you can tell you were hacked:

  • Email not delivering
  • People saying they didn’t get your email or calling as they haven’t heard from you
  • Weird inbox behavior
  • Your emails are missing from inbox
  • Your sent email are missing too
  • Unexpected password changes
  • Strange sent messages
  • Unfamiliar MFA prompts, new inbox rules, forwarding, or clients receiving fake invoices.

First thing I would do: (and if you need my help, use the form below to get in touch. I have same day appts available to help)

  • Look at your RSS feeds or conversation history folder and see if you find missing emails there, if so, most likely you have been hacked.
  • Log into your 365 account as admin, if you aren’t sure if you are admin, you should see this page admin.cloud.microsoft if you are
  • If you can’t see that page, then someone else is managing your 365 Admin account. Contact them to help with this request.
  • If you are the only admin and only have one account, then I recommend that you quickly make a second account and secure it so you can log in if you get locked out
  • Review your online sign on activity through Identity in Entra
  • Review your security settings/make sure all are yours
  • Log into your OWA online, look at all the rules. Hackers make rules with dots…or no name at all. Remove them all
  • Look for forwarding/rare these days as it flags you and the hackers don’t like that
  • Look at out of office/be sure there is none set up that you didn’t want
  • Check your restricted account status, you might be locked out from emailing
  • After reviewing and have a second global admin account setup, then I would reset the password
  • You can also sign out all accounts at that point as well.

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Category: New Outlook, Outlook Support

About the Author ()

Lisa Hendrickson is the owner of Call That Girl. She is an Outlook Expert and Microsoft 365 Consultant.

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