Microsoft 365 Error Codes

How to Fix Microsoft Office Account Errors 1200 and 80090016

Ayan Masood Oct 8, 2026 868 views

Question details

The user is unable to sign into Microsoft Office desktop applications due to account errors 1200 and 80090016 with a work account.

How to Fix Microsoft Office Account Errors 1200 and 80090016

Product: Microsoft Office Desktop Apps
Device & OS: Windows
Scenario: Attempting to sign into Microsoft Office desktop applications using a work or school account.
Observed behavior: The sign-in process fails with error codes 1200 and 80090016 on desktop applications, even though Office online and personal OneDrive accounts work correctly. Reinstalling the software does not resolve the issue as cached data persists.

Before you start

Ensure you have administrative privileges on your Windows computer and verify your Microsoft 365 work or school account credentials.

Solution 1Recommended

Disconnect Work Account and Clear Credential Manager

Use this solution to clear corrupted cached data and device registration files that cause sign-in loops and prevent Office from authenticating.

Errors 1200 and 80090016 usually occur because stale Microsoft and Office credentials get stuck in the Windows cache. Reinstalling Office does not wipe this system-level cache, so manual removal is required.

Disconnect the work account

Open Windows Settings, navigate to Accounts, and select 'Access work or school'. Locate the affected work or school account and click 'Disconnect'.

Open Credential Manager

Click the Windows Start button, type 'Credential Manager' in the search bar, and press Enter to open the utility.

Remove stale credentials

Select 'Windows Credentials'. Scroll through the list and click 'Remove' on any entries related to Microsoft Office, OneDrive, or your Microsoft 365 account.

Restart and sign in

Restart your computer to apply the changes. Open any Office desktop application and attempt to sign in again.

Disconnect Work Account and Clear Credential Manager

System Refresh: Clearing the credential manager forces Office to establish a completely new connection with the Microsoft authentication servers.

Solution 2

Contact Your Organization's Microsoft 365 Administrator

If you do not see a 'Disconnect' option for your work account, your organization's device registration policies are preventing local changes.

Free Microsoft Office alternative

Switch to WPS Office for a Hassle-Free Experience

If Microsoft Office account authentication errors are disrupting your workflow, consider switching to WPS Office. It provides a seamless, offline-friendly experience without the complicated Azure AD sync and device registration issues.

1. Download the software: Visit the official WPS Office website and download the free version for your operating system.
2. Install WPS Office: Run the setup file and follow the quick on-screen instructions to install the suite on your computer.
3. Open Microsoft formats directly: Launch WPS Office and instantly open your existing .docx, .xlsx, or .pptx files to continue working seamlessly.

No complex work account device registration or Azure AD sign-in required.Fully compatible with Microsoft Word, Excel, and PowerPoint formats (.docx, .xlsx, .pptx).Lightweight installation that opens files lightning fast without background syncing delays.Familiar user interface allowing you to transition with zero learning curve.

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Frequently Asked Questions

Why do I get error 1200 on desktop apps but not on Office online?

Error 1200 is typically related to the local Windows device's connection to Azure Active Directory (AAD) or corrupted local cached credentials. Office online uses browser session cookies and entirely bypasses local Windows device registration, which is why it continues to work.

Why is there no 'Disconnect' option under Access work or school?

Your organization's IT department has likely enforced Mobile Device Management (MDM) or group policies that restrict users from manually unregistering their devices or removing corporate accounts.

Will reinstalling Microsoft Office fix error 80090016?

Usually, no. Uninstalling and reinstalling the Microsoft Office suite does not remove the underlying Windows credential cache or device registration tokens that cause error 80090016. The credential cache must be cleared manually.

Microsoft Office Error Codes