[Fix] Can’t sign in to Microsoft 365

What causes [Fix] Can’t sign in to Microsoft 365?

Incorrect credentials
Account lock
Glitch in the system
Outdated or corrupt stored credentials

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Hello. I can't sign in to Microsoft 365. I am sure I am using the correct password. How do I fix this?

Microsoft 365 is a cloud-based productivity suite that includes various services such as Exchange Online, SharePoint, OneDrive, Skype for Business, and more. It offers users a centralized platform to access their work data from anywhere, and collaborate with their team effectively.

However, users may experience issues with signing in to their Microsoft 365 account, which can lead to frustration and hindrance in their workflow. A possible reason for this issue could be incorrect credentials, an account lock, or a glitch in the system.

One may think that typing the wrong password is just for old people or for those who still use flip phones, but even the most tech-savvy of us can fall victim to typos. So, before attempting any troubleshooting steps, users should check if their account isn't locked, and check their password manager to ensure they're using the right credentials.

Additionally, they should also make sure that their keyboard layout isn't accidentally changed, as typing in the wrong characters can cause sign-in issues. Restarting the app and rebooting the computer can often fix the glitch, and restore normal functionality.

In this guide, you will find 4 steps that should help you sign in to Microsoft 365 without issue. Keep in mind, that this may also be caused by underlying system issues. You can use a maintenance tool like [d1] that can fix most system errors, BSODs,[ref en-1] corrupted files, registry[ref en-2] issues, or clear cookies and cache[ref en-3] automatically. Otherwise, follow the step-by-step instructions below.

Solution 1. Remove Stored Credentials

Stored Credentials refer to the usernames and passwords that are saved on your computer for easy access to various accounts and websites. These credentials are stored in the Credential Manager, a feature of the Windows operating system.

Removing Stored Credentials can fix sign-in issues with Microsoft 365, or other websites and applications, because sometimes these stored credentials can become outdated or corrupt, leading to authentication errors. Removing the stored credentials forces the computer to request new credentials the next time you sign in, which can resolve the issue.

Launch Control Panel
Click the View by menu and select Large icons
Go to Credential Manager
Select Windows Credentials

Check Generic Credentials list
Click on the desired Microsoft 365 credential
Select Remove
Confirm the action in a pop-up window
Restart your PC

Solution 2. Create a New Local Account

Press the Windows key + I or go to Start menu and search for settings
Navigate to Accounts > Family & other users
Click on Add account
Select I don’t have this person’s sign-in information

Click Add a user without a Microsoft account and select Next
Enter a relevant username and password
Set up relevant security questions
Click Next and an account will be created

Solution 3. Repair Microsoft 365

Right-click on the Start button
Go to Apps and features
Find Microsoft 365 in the list of installed apps
Click the three-dot icon next to it
Click Modify
Select Quick repair option

Click Repair to start the process

Solution 4. Disable Modern Authentification

Modern Authentication is a security feature in Windows that enhances the authentication process for accessing various services and applications, including Microsoft 365. It enables multi-factor authentication and conditional access for enhanced security.

In some cases, disabling Modern Authentication may resolve sign-in issues with Microsoft 365 because it can sometimes interfere with the authentication process. When disabled, the system will revert to basic authentication, which may resolve any issues caused by the more advanced Modern Authentication process.

Press the Windows key + R to open a Run dialog
Type regedit and press Enter
Go to HKEY_CURRENT_USER > Software > Microsoft > Office > 16.0 > Common > Identity
In the right pane, create a new DWORD (32-bit) Value
Name it EnableADAL
Set Base to Hexadecimal
Set Value data to 0

Click OK to save your new system settings
Restart your computer
Try to sign in to your Microsoft 365 account

Bottom line

To resolve the sign-in issue with Microsoft 365, users should check their account status, verify their credentials, and ensure their keyboard layout is correct. Additionally, removing stored credentials from the Credential Manager may help. If these steps do not work, consider using a maintenance tool to address underlying system issues.

Frequently asked questions

What should I do if I can't sign in to Microsoft 365 on Windows 10?

First, check your internet connection and ensure that your Windows 10 is updated. If the problem persists, try resetting your Microsoft account password and clearing the browser cache.

How can I resolve sign-in issues for Microsoft 365 on Windows 11?

On Windows 11, ensure that your device's date and time settings are correct, as this can affect authentication. Additionally, try signing in using a different browser or the Microsoft 365 app.

What if I receive an error message when signing into Microsoft 365 on Windows?

If you encounter an error message, note the specific code or description provided, then visit the Microsoft support site for troubleshooting steps tailored to that error. Also, consider checking for any updates for Windows 10 or Windows 11 that might resolve the issue.

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Written & verified by

Gabriel E. Hall

Malware Removal Expert

Malware removal Ransomware recovery Browser hijackers Spyware analysis Security tools testing

Gabriel E. Hall is a malware removal expert and cybersecurity researcher with over ten years of hands-on experience analysing threats and writing removal guides. She has documented hundreds of malware families — from browser hijackers and adware to ransomware and rootkits — providing step-by-step cleanup instructions tested against real infections. Gabriel's work combines deep technical analysis with clear, actionable language that readers without a security background can follow. Her guides consistently appear among the most-referenced resources for malware removal on Windows systems.

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