How to Fix Office 365 Error Code 0xc0090030 in Teams & Outlook

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If you’ve been trying to sign in to Microsoft Teams or Outlook with your work account and keep running into the error “Unknown error code: 0xc0090030”, you’re not alone.

The strange part? Your Windows login works fine – but the Office 365 desktop apps refuse to cooperate.

This guide covers the one fix that works most often, as well as other troubleshooting methods to help you get back online quickly.

Why This Error Happens

Error 0xc0090030 is often linked to:

  • Corrupted sign-in tokens in Office apps
  • Stale or broken stored credentials
  • Problems with the Trusted Platform Module (TPM)
  • Domain or identity sync issues

Quick Fix: The Method That Works Most Often

From experience, the fastest and most reliable way to fix this error is:

  1. Remove the computer from Active Directory.
  2. Restart your PC.
  3. Rejoin it to your domain.

This resets the authentication relationship between your device and the domain, clearing any hidden token or certificate issues.

Other Troubleshooting Methods

1. Sign Out of Office Apps Completely

  • Open any Office app (Word, Outlook, Teams).
  • Go to File > Account.
  • Under User Information, click Sign Out for all accounts.
  • Close all Office apps completely.

2. Remove Saved Office 365 Credentials

Sometimes old credentials cause Office to get stuck.

  1. Open Control Panel.
  2. Go to User Accounts > Credential Manager > Windows Credentials.
  3. Remove anything related to Office 365, Teams, or Outlook.

3. Clear Identity Data in the Registry

Backup your registry before making changes.

  1. Run regedit.
  2. Go to: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity
  3. Delete the Identity folder.

4. Clear the TPM (Trusted Platform Module)

  1. Backup any data protected by TPM keys (e.g., PIN, virtual smart card).
  2. Open Windows Security > Device Security > Security Processor details > Security Processor troubleshooting.
  3. Click Clear TPM and restart.

Final Thoughts

While there are multiple ways to approach error 0xc0090030, rejoining your computer to the domain is often the quickest and surest fix. If you’re not in a position to do that right away, try clearing your credentials, registry identity keys, and TPM to resolve the sign-in problem.

FAQs:

1. What causes error code 0xc0090030 in Teams & Outlook?
It’s usually due to corrupted tokens, old credentials, or domain authentication issues.

2. Is rejoining the domain safe?
Yes, but it should be done by an IT admin to ensure you don’t lose access to network resources.

3. Will clearing the TPM delete my files?
No, but it will remove TPM-protected keys, so you should back up any dependent data first.

4. Do I need to reinstall Office to fix this?
Usually, no — removing credentials, clearing registry entries, and rejoining the domain are enough.

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