Microsoft 365 Error Codes

Fix Microsoft 365 Account Error and Synchronization Issues (Code 29)

Maira Mehtab Sep 24, 2026 870 views

Question details

The user is experiencing repeated account or device errors in Microsoft 365 applications that prevent successful data synchronization.

Product: Microsoft 365
Device & OS: not provided
Scenario: Attempting to sign in and synchronize data within Microsoft Office applications, but persistent authentication prompts and errors block the process.
Observed behavior: Applications repeatedly display an account or device error after sign-in. Repeated authentication attempts fail to resolve the problem, often resulting in Error Code 29.

Before you start

Ensure all Microsoft Office applications are completely closed before proceeding, and create a backup of your Windows Registry before making any modifications to identity keys.

Solution 1Recommended

Clear Office Identity Caches and Registry Entries

Use this method to clear out corrupted authentication tokens that trigger Error Code 29 during Microsoft 365 license checks.

When Microsoft 365 fails to synchronize and repeatedly prompts for authentication, the local identity cache or registry entries may be corrupted. Clearing these cached credentials forces Office to generate new, clean authentication tokens upon your next sign-in.

Identify the Error Code

Open Microsoft Word, go to File > Account, and click on Update License. Note the resulting error code to confirm if it is Error Code 29.

Remove Authentication Folders

Close all Office applications. Navigate to your local AppData directory and delete or rename both the 'OneAuth' and 'IdentityCache' folders.

Delete Office Identity Registry Key

Open the Windows Registry Editor (regedit) and carefully locate and delete the Office Identity registry key associated with your Microsoft account.

Repair or Update Office

If the issue persists, run the Office update or repair tool using the OfficeC2RClient command in the Command Prompt to restore missing components.

Registry Editing Caution: Exercise extreme caution when editing the Windows Registry. Deleting the wrong keys can affect system stability, so always back up the registry before proceeding.

Free Microsoft Office alternative

Try WPS Office for a Hassle-Free Experience

If you are tired of dealing with persistent Microsoft 365 account synchronization issues and registry errors, consider switching to WPS Office. It provides a lightweight, highly compatible, and free alternative to Microsoft Office, completely bypassing complex account sync requirements for your daily tasks.

1. Download WPS Office: Visit the official WPS website and download the free installer.
2. Install the Software: Run the installer and follow the quick, lightweight setup process.
3. Open Your Files Instantly: Open and edit your existing Word, Excel, and PowerPoint files offline without dealing with account sign-in loops.

Seamlessly compatible with all major Microsoft Office formats (.docx, .xlsx, .pptx).No forced cloud account synchronization required for basic offline document editing.Lightweight installation with a familiar, easy-to-use tabbed interface.Free to use with built-in PDF editing and format conversion tools.

microsoft office alternative - wps office

Frequently Asked Questions

What does Microsoft 365 Error Code 29 mean?

Error Code 29 typically indicates a conflict or corruption within your locally cached account credentials or the Office identity registry keys, which prevents your account from authenticating properly with Microsoft servers.

Where can I find the OneAuth and IdentityCache folders?

These folders are located in the hidden AppData directory on your Windows user profile, specifically under Local\Microsoft\IdentityCache and Local\Microsoft\OneAuth. You will need to enable 'Hidden items' in Windows File Explorer's View tab to access them.

How do I run the OfficeC2RClient command?

Open the Command Prompt as an administrator, navigate to the Common Files\Microsoft Shared\ClickToRun folder, and type the command 'OfficeC2RClient.exe /update user updatepromptuser=true' to trigger the update and repair process.

Can I use Microsoft Office without signing in?

Microsoft 365 requires periodic sign-ins to verify your active subscription and synchronize settings. If you prefer to work entirely offline without account verification, you may want to use a free alternative like WPS Office.

Microsoft Office Error Codes