How To Stop Microsoft Outlook Windows Security Pop Up

To stop repeated Windows Security pop-ups in Microsoft Outlook, check that your email account can sign in, then address the cause: outdated saved credentials, an Outlook connection problem, or an organisation’s authentication settings. For classic Outlook, targeted credential removal and profile repair may help. If.

Identify which security prompt is appearing

A window labelled Windows Security asking for a username and password is an authentication request. Repeated requests suggest that Outlook cannot complete or retain the sign-in. A warning about an expired, untrusted or mismatched certificate concerns the server’s identity and needs a different fix.

These prompts are separate from antivirus notifications. Our Windows Security guides cover Windows protection settings, but turning off those notifications will not repair Outlook authentication.

If the screen instead asks you to press Ctrl+Alt+Delete before signing in to Windows, see the guide to the Windows Security button on a Lenovo ThinkPad. That Windows sign-in step is separate from an email password request.

Note the affected email address, any server name and the exact error text. Also check whether you use classic Outlook or new Outlook. The File menu, COM add-ins and Mail profiles discussed below belong to classic Outlook; Microsoft explains that new Outlook uses a different architecture, without the same profile and safe-mode troubleshooting.

Check the account before changing Outlook

1. Close Outlook and open your email provider’s official webmail site by navigating there yourself. Sign in with the affected account.
2. If webmail rejects the password, resolve the account problem first. Use the provider’s password recovery process or contact your workplace IT team. Repeatedly entering the same rejected password in Outlook will not fix it.
3. If webmail works, reopen Outlook and select the correct account in any legitimate sign-in window. Complete any required multifactor authentication.
4. Restart the computer and check that its date, time and time zone are correct. Confirm that your internet connection works and connect to your organisation’s VPN if its email service requires it.

Webmail working narrows the investigation towards the desktop connection, but it does not prove that Outlook’s access is permitted. A workplace may apply different access rules to browsers and desktop apps.

If several colleagues are affected at once, ask IT to check the mail service and sign-in systems before making changes on individual computers.

Remove a stale saved credential in classic Outlook

A saved password can become outdated after an account change. Microsoft documents stored credentials as a cause of repeated prompts in older Outlook configurations. Removing a relevant entry can help where that credential is being used; it is not a universal reset for modern Microsoft 365 sign-in.

1. Close Outlook and other Office applications.
2. Search the Windows Start menu for Credential Manager and open it. Select Windows Credentials.
3. Inspect entries associated with the affected Outlook account or mail server. Remove only an entry you can confidently identify as relevant. If the names are unclear, ask IT to identify it.
4. Reopen Outlook, enter the current account credentials when requested and complete any additional verification.
5. Close and reopen Outlook again to check whether the prompt returns.

Removing a saved credential can require another sign-in for an application that shares it. Avoid clearing every Windows or Office credential as a blanket fix, and leave unrelated accounts alone.

If you are navigating through Control Panel, Credential Manager is under User Accounts. The guide to finding System and Security in Windows 10 explains the category layout; you need the User Accounts category for this task.

Check updates, add-ins and the Outlook profile

Install available Windows and Office updates through their normal update controls, then restart when requested. On a managed computer, follow your organisation’s update process.

Test whether an add-in is involved

For classic Outlook, Microsoft’s safe-mode troubleshooting provides a way to test without the usual add-ins. Use this as a diagnostic check if the prompt continues.

1. Close Outlook. Press Windows+R, type outlook.exe /safe and press Enter.
2. Select your usual profile if asked, then check whether the repeated prompt occurs.
3. If the problem disappears, open File > Options > Add-ins. Choose COM Add-ins in the Manage list and select Go.
4. Record which add-ins are enabled, then temporarily clear their checkboxes. Restart Outlook normally.
5. Re-enable add-ins one at a time, restarting and checking between changes, to identify whether one triggers the prompt.

If you identify an add-in, update it or contact its supplier. Keep a workplace-required add-in under IT’s guidance.

Repair the account connection

1. In classic Outlook, open File > Account Settings > Account Settings.
2. On the Email tab, select the affected account and choose Repair if available.
3. Follow the prompts and restart Outlook.

Microsoft’s profile repair instructions note that availability depends on the account and Outlook configuration. If Repair is unavailable or fails, ask IT about testing a new profile while preserving the existing profile and any local mail archives.

Handle certificate and organisation sign-in problems separately

If the warning mentions a certificate, check the computer’s clock and record the server name and certificate error. Do not install a certificate merely to dismiss the warning. A name mismatch can require the provider or administrator to correct the certificate or server configuration, as described in Microsoft’s guidance on Outlook certificate mismatches.

For a work or school account, ask IT to check authentication policies, account restrictions and the sign-in logs. Do not disable multifactor authentication or change authentication registry settings to suppress a prompt.

Leave automatic image-download protection, antivirus and firewall protection enabled while investigating. Changing those settings does not establish why Outlook is failing to sign in.

If the prompt persists, send your IT team or email provider the exact message, Outlook edition, affected account, webmail test result and the troubleshooting steps already completed. Exclude passwords and verification codes.