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Summary: Microsoft Office 365 offers a wide range of applications and services for enhanced productivity, but users may encounter rare errors like 801C03F2 when signing in. This article explores methods to resolve this issue, whether it’s system-related or an Office 365 application problem. Solutions include disk clean-up, system reboot, Wi-Fi checks, and clearing Credential Manager data for system issues, while restarting, repairing, or reinstalling Office 365 applications can address application-related problems.

Microsoft’s Office 365 is widely adopted by both organizations and individuals to significantly enhance the management of work-related tasks and responsibilities. With millions of users, it offers a diverse range of applications and services, making it far more than a mere email platform.

But all this goes in vain if you are not even able to smoothly sign in to your Office 365 account.

Office 365 is undoubtedly an advanced platform, but it’s not immune to occasional rare errors like the error code 801C03F2. Some users have encountered this issue during login attempts, often attributed to file corruption. While it may appear complex, resolving it can be relatively straightforward.

Here, we will be discussing all the methods on how to fix the error code 801C03F2 in Office 365.

This issue can arise from problems within the system or an Office 365 application. If the system is the culprit, then the following methods can help resolve it:

  • Perform Disk Clean-up
  • Reboot the system
  • Check the Wi-Fi connection
  • Clear the Credential Manager’s data

However, if the problem is due to an Office 365 application, these techniques will help you-

  • Restart the application
  • Repair Office 365 applications
  • Reinstall the Office 365 applications

For a better understanding, all these methods have been discussed in length below-

Perform Disk Clean-up

Disk Clean-up is an inbuilt utility that safely removes unnecessary files and folders, enhancing overall system performance. Regular maintenance clean-ups can optimize its functionality. Here are the steps to run Disk Clean-up:

  1. Press the Windows key and X simultaneously to open the Task menu. Select the Run option.Select the Run
  2. Type cleanmgr and click on OK.Type cleanmgr and click on OK
Reboot the system

Rebooting your system is a commonly recommended troubleshooting method. It closes all running applications and unloads drivers before restarting the operating system. This action can often resolve error code 801C03F2.

Check your Wi-Fi connection

This error may arise from undetermined network issues, hindering users from signing into their accounts. To address this, you can try restarting your modem and router by turning them off and then back on after a few minutes. If connectivity problems persist, consider connecting to a more stable and robust network.

Clear the Credential Manager data

This utility permits users to view and manage their login credentials for various websites and applications. However, there are instances where it can lead to authentication issues.

You can clear the Credential Manager using these steps-

  1. Move to Control Panel and select Credential Credential Manager
  2. Click on Windows Credentials.Windows Credentials
  3. Choose the password which you want to delete and then, select Remove.
  4. To apply the changes, restart your computer.
Restart the Office 365 application

Minor issues can occasionally affect the currently running Office application. If any of the Office applications aren’t functioning correctly, a simple solution is to close and relaunch the application. Verify if the error code persists.

Repair the Office 365 applications

Another effective method to resolve error code 801C03F2 is to repair the applications within the Office suite. Additionally, this error may be linked to insufficient storage space, which you can address by increasing your Office 365 mailbox size to 100GB. To perform the repair process, follow these steps:

  1. Right-click on the Start button present in the extreme bottom left corner and click on Programs and on Programs and Features
  2. Select the Office application and click on Modify and this will repair all the Office applications.
  3. Follow the instructions presented on the screen to successfully complete the process.
Reinstall the Office 365 application

Frequently, these errors are triggered by unidentified issues. One effective workaround is to uninstall the Office 365 application and then reinstall it, providing users with a clean slate to start fresh. To uninstall the program, access the Control Panel, and then reinstall it from the official Microsoft website.

What to do if you lose your data due to Office 365 errors?

Data loss is a common risk, even with minor errors. It’s crucial to protect your data with regular backups, especially in scenarios involve in the deleted user mailboxes in Exchange online. Backups ensure uninterrupted work by enabling data restoration. Given the confidential nature of data, selecting a secure backup tool is paramount.

The Kernel Office 365 Backup & Restore tool is a professional utility designed to securely back up your critical data. You can easily restore these backed-up data whenever needed. It offers a wide range of options for selecting the backup file format. Additionally, it allows users to perform selective Office 365 data backup. This software is compatible with all plans and versions of Microsoft Outlook and Exchange Server, ensuring comprehensive support.


The error code 801C03F2 is experienced by users when they try to sign in to their Office 365 accounts. This can occur due to problems with the system or an Office application. Accordingly, some methods can be put to use to resolve this error- perform a disk clean up, reboot the system, check your internet connection, clear the data of Credential Manager, close and relaunch the Office 365 app, repair the Office applications and remove/reinstall the Office 365 application. And it is a wise decision to take backup of all your data using a professional utility.