0x80090016 Error: Key Storage Provider (KSP) Error

1.  Remove and Recreate the PIN (Windows Hello Users)

If you’re encountering the error during login or app startup:

1. Go to Settings → Accounts → Sign-in options.
2. Under PIN (Windows Hello), click Remove.
3. Reboot your system.
4. Go back and click Add PIN to set a new one.

2. Delete and Rebuild the Ngc Folder (Admin Access Required)

 This step removes stored PINs and may affect fingerprint/Hello authentication.

1. Press Win + R, type: C:\Windows\ServiceProfiles\LocalService\AppData\Local\Microsoft\NGC
2. Delete all contents in this folder.
3. Reboot and set a new PIN or sign-in method.

3. Run System File Checker and DISM

To restore corrupted system components:

sfc /scannow

DISM /Online /Cleanup-Image /RestoreHealth

1. Open Command Prompt as Administrator.
2. Run the above commands one after the other.
3. Restart your PC.

4. Check Credential Manager

1. Open Control Panel → Credential Manager → Windows Credentials.
2. Remove any problematic saved entries (e.g., related to Outlook, MicrosoftAccount, or Office).
3. Try logging in or relaunching Outlook again.

5. TPM Reset (if BitLocker is involved)

1. Open tpm.msc via Run (Win + R).
2. Click Clear TPM (ensure you have a recovery key if BitLocker is used).
3. Reboot and reinitialize key services.

6. Create a New Windows User Profile (If Applicable)

Sometimes, the existing profile is too damaged for repair:

• Go to Settings → Accounts → Family & other users.
• Click Add someone else to this PC.
• Create a new user, switch to it, and check if the issue persists.