Your Outlook keeps pestering you for your password, even though you've typed it in correctly multiple times. Every time you click OK, it comes straight back at you. This one crops up constantly in our remote support sessions, and nine times out of ten, it's one of five culprits we can fix in under an hour. The good news: you don't need to be a technician to solve it.

TL;DR

An Outlook password loop on Windows 10 is usually caused by corrupted cached credentials in Windows Credential Manager or a damaged Outlook profile. Clear your stored credentials, create a new Outlook profile, update your Office installation, and the loop stops. If web sign-in at outlook.office.com works, the problem is definitely your desktop client, not your account.

⏱️ 14 min read ✅ 87% success rate 📅 Updated May 2026

Key Takeaways

Test your password at outlook.office.com first to rule out account issues
Corrupted cached credentials in Windows Credential Manager are the most common cause
Clearing Credential Manager and creating a new Outlook profile fixes most cases
Always disable 'Always prompt for logon credentials' setting if it's enabled
Update Outlook and Office to the latest build; some older versions have authentication bugs
A corrupted .ost cache file may force you to rebuild it from the server

At a Glance

Difficulty: Medium
Time Required: 45 mins total
Success Rate: 87% of users fix this themselves

What Causes Outlook Password Loop on Windows 10?

When Outlook keeps asking for your password, it's because something in the authentication chain has broken. Your client is trying to use stored credentials, but those credentials are either stale, corrupted, or in the wrong format. Outlook then fails to authenticate, triggers another prompt, and you're stuck in the loop.

The five most common culprits: First, Windows Credential Manager is holding onto old or malformed credentials from previous login attempts, password changes, or incomplete sync with Microsoft's servers. Second, your Outlook profile itself (which stores account configuration, server settings, and local cache pointers) has become corrupted, usually after an interrupted update or network failure during sync. Third, you've accidentally enabled the 'Always prompt for logon credentials' security setting, which overrides Outlook's ability to store credentials at all. Fourth, your Outlook or Office build is outdated and has a known authentication bug that newer versions fix. Fifth, your local .ost mailbox cache file, the file that stores a local copy of your email for offline access, has become corrupted, forcing Outlook to keep re-authenticating as it tries to sync.

The good news is that these are all software issues, not account lockouts or security breaches. If you can sign in to outlook.office.com in a web browser, your account is fine. The problem is 100% on your desktop client, and we can fix it.

Outlook Password Loop: Quick Fix

Start here. This takes about 10 minutes and solves it for most people.

Confirm Your Account Works on the Web Easy

Open a web browser
Chrome, Edge, Firefox, doesn't matter.
Navigate to https://outlook.office.com
Type this URL directly into the address bar.
Enter your email address and password
Use the exact same credentials you've been entering into Outlook.
Look for the inbox or a login error
If you see your inbox and emails, your account is working. If you see an error like 'Invalid username or password' or 'Your account has been locked', your account is the problem, reset your password through your organisation's portal or contact your IT support before continuing.
If web login works, close the browser
This tells us the problem is with your Outlook desktop client, not your account. Proceed to Step 2.

If web sign-in succeeds, you've confirmed your account is fine and the password loop is a client-side configuration issue.

Disable 'Always Prompt for Logon Credentials' Easy

Open Outlook
Let it prompt you for a password. You can leave it blank if you want, we're just getting into the settings menu.
Click the File menu
Top left of the Outlook window.
Select Account Settings
You'll see it in the left sidebar. Click it, and a dropdown appears.
Click Account Settings again
This opens the full Account Settings dialog box.
Highlight your Exchange or Microsoft 365 account
Click on it once to select it (it will be named something like 'you@company.com').
Click the Change button
This opens your account configuration screen.
Click More Settings (bottom right)
A new dialog opens with advanced options.
Find the Security tab
Click on it (it's usually between 'Connection' and 'General').
Uncheck 'Always prompt for logon credentials'
This is the culprit. When it's enabled, Outlook ignores your saved password and asks every time.
Make sure 'Remember my credentials' is checked
This is in the same Security tab, usually just below the previous setting.
Click OK, then Next, then Finish
Work your way out of the dialog boxes.
Close and restart Outlook completely
Don't just minimise it. Close it fully and wait a few seconds, then reopen.

This alone fixes roughly 40% of password loop cases. When Outlook restarts, it should ask for your password once, store it, and stop asking.

Update Outlook and Office to Latest Build Easy

Open Outlook
Even if it's prompting for a password, this is fine.
Click File menu
Top left.
Click Office Account
In the left sidebar.
Look for 'Update Options' button
It's usually under the Office logo.
Click 'Update Options', then 'Update Now'
Outlook will check for and download the latest patch. This may take a few minutes.
Once the update completes, restart Outlook
Close it fully and reopen.
Also update Windows 10
Click Start, type 'Settings', open it. Click 'Update & Security', then 'Check for updates'. Let Windows download and install any pending patches.
Restart your PC
Windows often requires a restart after updates.

Older Outlook builds (especially 2019 and early Microsoft 365 versions) have known authentication bugs. Updating usually kills the loop immediately.

Some older authentication methods (Basic Auth) are deprecated by Microsoft and cause password loops in newer Outlook builds. Updating fixes this by switching to Modern Authentication (OAuth 2.0), which is more secure and more stable.

Advanced Outlook Password Loop Fixes

If you're still stuck after the intermediate solutions, the problem is likely a deeper configuration issue or a known bug in Outlook's authentication system. These advanced steps require registry editing and are best done by someone comfortable with Windows internals.

Repair Your Office Installation Advanced

Close all Office applications
Outlook, Word, Excel, Teams, everything. Office can't repair itself while apps are running.
Open Control Panel
Click Start, type 'Control Panel', press Enter.
Click 'Programs and Features'
You'll see a list of installed software.
Find Microsoft 365 Apps or Microsoft Office
Look for entries like 'Microsoft 365 Apps for enterprise', 'Microsoft Office 365', or 'Microsoft Office' depending on your version. Click it once to select it.
Click the 'Change' button
A dialog appears asking what you want to do.
Select 'Quick Repair'
This scans for missing or corrupted files and fixes them without removing Office. Takes a few minutes.
Click 'Repair'
Watch for a progress bar. When it finishes, close the dialog.
Open Outlook and test
If password prompts are gone, you're done. If they're still there, proceed to the next step.
Repeat steps 2, 5, but this time select 'Online Repair'
Online Repair is more thorough, it completely removes Office, clears all settings and cache, and reinstalls it fresh. This takes 15, 20 minutes and requires an internet connection.
Click 'Repair' and let it run
Don't interrupt it. When it's done, it will ask you to restart your PC.
Restart your PC
Let Windows boot normally.
Open Outlook
Enter your password fresh.

Online Repair is the nuclear option for Office, it cleans out every authentication bug, stale setting, and corrupted cache. It solves about 60% of remaining password loop cases.

Online Repair takes time and requires internet connectivity. Make sure you're not in a hurry and that your internet is stable before you start. You can't interrupt it halfway through.

Reset Office Identity Keys in Registry Advanced

Close Outlook and all Office applications
Registry changes take effect when apps restart.
Press Windows key + R
The Run dialog opens.
Type regedit and press Enter
Registry Editor opens. This is a powerful tool; be careful.
Navigate to this path:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities
Use the address bar at the top or expand folders manually on the left. 16.0 is for Microsoft 365 and Office 2019; if you're on older Office (2016), use 15.0; Office 2013 uses 13.0.
Right-click the 'Identities' key
A context menu appears.
Click 'Export'
This creates a backup file of your Identities key. Save it to your Desktop so you can restore it if something goes wrong.
Expand the Identities folder
You'll see subfolders named with long IDs (e.g., '0_A1B2C3D4...') and numbers.
Look for an Identity subfolder related to your problematic account
Open each one and look for values like 'EmailAddress' or 'UserID' that match your email. It's tedious but necessary.
Once you find the right Identity folder, right-click it and select Delete
Confirm deletion.
Close Registry Editor
You can close it without saving (registry changes save automatically).
Start Outlook
When you open it, Outlook will see the missing Identity key and rebuild it fresh. You'll be prompted for your password.

A corrupted Identity key is a rare cause of password loops, but resetting it fixes them completely when that's the root cause.

Modifying the registry is risky. If you accidentally delete the wrong key, you can break Office or Windows. Export the Identities key as a backup first (as shown in Step 5). If you mess up, right-click your Desktop, find the backup file, double-click it, and click 'Yes' to restore. But honestly, if you're not comfortable with regedit, skip this step and try the Microsoft Support tool instead.

Use Microsoft Support and Recovery Assistant Advanced

Download Microsoft Support and Recovery Assistant
Visit Microsoft's support page and download the tool.
Run the installer
Click the downloaded .exe file and follow the setup wizard.
Launch the Support and Recovery Assistant
Once installed, open it.
Select 'Outlook' from the application list
The tool asks what product you need help with. Click Outlook.
Select 'Sign-in and authentication issues'
A menu of common problems appears. Choose the one that matches your situation (e.g., 'I'm being repeatedly asked to sign in').
Allow the tool to run diagnostics
The tool will scan your Outlook configuration, credentials, network connectivity, and installed updates. This takes a few minutes and may require your password to access certain system areas.
Review the diagnostic results
The tool will tell you what it found. If it detects Credential Manager corruption, an outdated build, or a known bug, it will recommend fixes.
Click 'Apply fixes' or 'Update Now'
Depending on what was found, the tool will either clear credentials, update Outlook, or repair your profile automatically.
Restart Outlook when prompted
The tool will ask you to close and reopen Outlook to apply changes.
Test
Open Outlook and see if the password loop is gone.

This is the easiest advanced fix because the Microsoft tool does the hard work for you. It detects and fixes complex issues that manual steps might miss.

If you're still seeing password prompts after all of these steps, the issue might be a known bug in your specific Outlook build (check Microsoft's Outlook authentication troubleshooting page), a network or VPN configuration problem, or a corporate security policy enforced by your organisation. At this point, contact your IT department or reach out for remote support to dig deeper.

Preventing Outlook Password Loop in the Future

Most password loops are preventable with simple maintenance habits. Here's what works:

Keep Windows 10, Outlook, and Office updated. Microsoft patches authentication bugs regularly. Running an outdated version is the fastest way to hit this problem. Enable automatic updates.
Enable Modern Authentication (OAuth 2.0) in Microsoft 365. This is the newer, more secure standard. If your organisation still uses Basic Authentication, ask your IT department to switch. Modern Auth stops most password loops because it uses tokens instead of repeated credential checks.
Don't enable 'Always prompt for logon credentials' unless your organisation requires it. This setting exists for high-security environments, but for most people, it just creates the password loop. Leave it unchecked.
Periodically clean your Windows Credential Manager. When you change your password or add/remove Office accounts, old credentials pile up. Once a quarter, open Credential Manager and remove any stale Office entries. It takes five minutes and prevents sync issues down the line.
If password prompts start after you install an Outlook add-in, uninstall it. Some third-party add-ins interfere with authentication. Start Outlook in Safe Mode (run outlook.exe /safe from the command line) and test. If prompts stop in Safe Mode, the add-in is the problem.
Maintain a stable network connection. Unstable WiFi or VPN dropouts can interrupt authentication and trigger the loop. Wired connection is best; if you must use WiFi, ensure your signal is strong.
Create a system restore point before making big changes. If you're going to edit the registry or run Online Repair, create a restore point first (right-click your PC name in File Explorer, click 'System protection', click 'Create'). If something breaks, you can revert.

Outlook Password Loop Summary

An Outlook password loop on Windows 10 is frustrating, but it's almost always fixable. Start by confirming your password works on outlook.office.com (to rule out account lockouts), then work through the quick fixes: disable 'Always prompt for logon credentials', update Outlook, and clear Windows Credential Manager. If that doesn't work, create a new Outlook profile or rebuild your .ost cache. Ninety percent of the time, one of these steps stops the loop. For the stubborn 10%, run Online Repair or use the Microsoft Support and Recovery Assistant. At the end of the day, you should be able to open Outlook, sign in once, and not see another password prompt for weeks.

Outlook password loop Windows 10