{"id":2311,"date":"2026-03-24T17:47:56","date_gmt":"2026-03-24T12:17:56","guid":{"rendered":"https:\/\/mukundasoftware.com\/blog\/?p=2311"},"modified":"2026-03-24T17:54:18","modified_gmt":"2026-03-24T12:24:18","slug":"fix-required-authentication-broker-missing-outlook","status":"publish","type":"post","link":"https:\/\/mukundasoftware.com\/blog\/help\/outlook\/fix-required-authentication-broker-missing-outlook.html","title":{"rendered":"Fix: \u201cA Required Authentication Broker is Missing\u201d in Outlook &amp; Microsoft 365"},"content":{"rendered":"\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"wp-block-paragraph\"><strong>TL;DR:<\/strong> The most common fix is re\u2011registering the <strong>AAD Broker Plugin<\/strong> via PowerShell. Jump straight to <a href=\"#3-re-register-the-authentication-broker-via-powershell\"><strong>Solution 3<\/strong><\/a> to get back into Outlook quickly.<\/p>\n<\/blockquote>\n\n\n\n<p class=\"wp-block-paragraph\">If you\u2019re staring at the error <strong>\u201cA required authentication broker is missing\u201d<\/strong> while trying to sign in to the Outlook desktop app, you\u2019re not alone. This issue has been frustrating Microsoft 365 users across <strong>Windows 10 and 11<\/strong>, often blocking access to Teams, Excel, and other Office apps as well. The good news? It\u2019s usually fixable without reinstalling Windows.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What Causes This Error?<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The \u201c<strong>authentication broker<\/strong>\u201d is a core Windows component\u2014the <strong>Web Account Manager (WAM)<\/strong> \u2014that safely handles sign\u2011ins for Microsoft 365 apps. When it becomes corrupted, disabled, or blocked, desktop apps can\u2019t verify your credentials even though the web versions (outlook.office.com) continue to work.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Common triggers include:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A recent Windows Update or Office update.<\/li>\n\n\n\n<li>A password change or Multi\u2011Factor Authentication (MFA) reset.<\/li>\n\n\n\n<li>Third\u2011party antivirus or security software interfering.<\/li>\n\n\n\n<li>A corrupted user profile linked to device registration.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>How to Fix the \u201cAuthentication Broker Missing\u201d Error<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">These solutions are ordered from least invasive to most advanced. Try them in sequence.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">1. Restart the Web Account Manager Service<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Sometimes the service simply needs a restart.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Press <strong>Windows Key + R<\/strong>, type <code>services.msc<\/code>, and press <strong>Enter<\/strong>.<\/li>\n\n\n\n<li>Scroll down to <strong>Web Account Manager<\/strong>.<\/li>\n\n\n\n<li>Right\u2011click it and select <strong>Restart<\/strong>.<\/li>\n\n\n\n<li>Try signing into Outlook again.<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. Clear Windows Credentials<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Old cached credentials can block the new authentication flow.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Close all Microsoft 365 apps (Outlook, Teams, etc.).<\/li>\n\n\n\n<li>Open <strong>Control Panel<\/strong> \u2192 <strong>User Accounts<\/strong> \u2192 <strong>Credential Manager<\/strong>.<\/li>\n\n\n\n<li>Click <strong>Windows Credentials<\/strong>.<\/li>\n\n\n\n<li>Under <strong>Generic Credentials<\/strong>, look for entries containing <strong><code>MicrosoftOffice<\/code><\/strong> or <strong><code>ADAL<\/code><\/strong>.<\/li>\n\n\n\n<li>Click the arrow next to each one and select <strong>Remove<\/strong>.<\/li>\n\n\n\n<li>Restart your computer and try to sign in again.<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3. Re\u2011register the Authentication Broker via PowerShell<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">This is the most reliable fix recommended by Microsoft engineers. It re\u2011installs the broker plugin.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Close all Microsoft 365 apps.<\/li>\n\n\n\n<li>Open <strong>PowerShell<\/strong> (right\u2011click and choose <strong>Run as Administrator<\/strong>\u2014this ensures the command applies system\u2011wide).<\/li>\n\n\n\n<li>Copy and paste the following command (make sure the quotes are straight <code>\"<\/code> and not curly):<\/li>\n<\/ol>\n\n\n\n<pre class=\"wp-block-code\"><code>   Add-AppxPackage -Register \"$env:windir\\SystemApps\\Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy\\Appxmanifest.xml\" -DisableDevelopmentMode -ForceApplicationShutdown<\/code><\/pre>\n\n\n\n<ol start=\"4\" class=\"wp-block-list\">\n<li>Press <strong>Enter<\/strong> and wait for the operation to complete.<\/li>\n\n\n\n<li>Restart your device, then open Outlook and test the sign\u2011in.<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">4. Rename the AAD Broker Plugin Folder<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If re\u2011registering doesn\u2019t work, renaming the broker\u2019s data folder forces Windows to recreate a fresh copy.<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Close all Microsoft 365 apps.<\/li>\n\n\n\n<li>Press <strong>Windows Key + R<\/strong>, type <code>%localappdata%\\Packages<\/code>, and press <strong>Enter<\/strong>.<\/li>\n\n\n\n<li>Find the folder named <strong><code>Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy<\/code><\/strong>.<\/li>\n\n\n\n<li><strong>Rename<\/strong> it (right\u2011click \u2192 <strong>Rename<\/strong>) by adding <code>.old<\/code> to the end, e.g., <code>Microsoft.AAD.BrokerPlugin_cw5n1h2txyewy.old<\/code>.<\/li>\n\n\n\n<li>Restart your computer. Windows will automatically create a new, healthy copy of the folder.<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">5. Check Security Software &amp; Work\/School Account<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Third\u2011party antivirus:<\/strong> Temporarily disable (or uninstall) your antivirus to see if it\u2019s blocking the broker. If the error disappears, add an exclusion for the broker folder (<code>%localappdata%\\Packages\\Microsoft.AAD.BrokerPlugin_*<\/code>) or switch to a less intrusive security suite.<\/li>\n\n\n\n<li><strong>Work\/School account:<\/strong> Go to <strong>Settings<\/strong> \u2192 <strong>Accounts<\/strong> \u2192 <strong>Access work or school<\/strong>. If your account is listed, try <strong>Disconnect<\/strong> then <strong>Connect<\/strong> again. This refreshes your device registration with Azure AD.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">6. Use the Web Apps as a Temporary Workaround<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If you need immediate access while troubleshooting, remember that the web versions of Outlook, Teams, and Office work perfectly. Go to <strong>outlook.office.com<\/strong> to check your email.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>When to Contact Your IT Admin<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">If your device is managed by an organization (company or school), you may encounter this error due to Intune policies or device enrollment restrictions. If none of the steps above resolve the issue, contact your <strong>System Administrator<\/strong>. They may need to check device registration or provide a fix specific to your environment.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Helpful Resources &amp; Links<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">For further reading, these official Microsoft Q&amp;A threads provide additional context and solutions:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>[Microsoft Q&amp;A] Getting error while accessing outlook, teams and excel<\/strong><br><a href=\"https:\/\/learn.microsoft.com\/en-au\/answers\/questions\/5819705\/getting-error-while-accessing-outlook-teams-and-ex\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/learn.microsoft.com\/en-au\/answers\/questions\/5819705\/getting-error-while-accessing-outlook-teams-and-ex<\/a><\/li>\n\n\n\n<li><strong>[Microsoft Q&amp;A] A required authentication broker is missing, how do I fix it?<\/strong><br><a href=\"https:\/\/learn.microsoft.com\/en-us\/answers\/questions\/5233468\/a-required-authentication-broker-is-missing-how-do\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/learn.microsoft.com\/en-us\/answers\/questions\/5233468\/a-required-authentication-broker-is-missing-how-do<\/a><\/li>\n\n\n\n<li><strong>[Microsoft Q&amp;A] Windows 11 Authentication and Taskbar Issues<\/strong><br><a href=\"https:\/\/learn.microsoft.com\/en-nz\/answers\/questions\/2283173\/windows-11-authentication-and-taskbar-issues\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/learn.microsoft.com\/en-nz\/answers\/questions\/2283173\/windows-11-authentication-and-taskbar-issues<\/a><\/li>\n\n\n\n<li><strong>[Microsoft Q&amp;A] How do I edit Web Account Manager? (365 Outlook password problem)<\/strong><br><a href=\"https:\/\/learn.microsoft.com\/en-us\/answers\/questions\/4516963\/how-do-i-edit-web-account-manager-(365-outlook-pas\" rel=\"nofollow noopener\" target=\"_blank\">https:\/\/learn.microsoft.com\/en-us\/answers\/questions\/4516963\/how-do-i-edit-web-account-manager-(365-outlook-pas<\/a><\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Looking for more ways to boost your Microsoft 365 productivity? Check out our guide: [Top 10 Microsoft 365 Productivity Tips for 2026] \u2013 link to another Mukunda Software post.<\/em><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading has-text-align-center\">Related Reads<\/h2>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-8f761849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-mukunda-software-updates wp-block-embed-mukunda-software-updates\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"CDVjq7Du5D\"><a href=\"https:\/\/mukundasoftware.com\/blog\/help\/outlook\/fix-msoutlook-error-0x8004010f-pst-file-access.html\">Fix &#8220;PST File Cannot Be Accessed (0x8004010F)&#8221; Error in Outlook<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"&#8220;Fix &#8220;PST File Cannot Be Accessed (0x8004010F)&#8221; Error in Outlook&#8221; &#8212; Mukunda Software Updates\" src=\"https:\/\/mukundasoftware.com\/blog\/help\/outlook\/fix-msoutlook-error-0x8004010f-pst-file-access.html\/embed#?secret=BYWJli4eXK#?secret=CDVjq7Du5D\" data-secret=\"CDVjq7Du5D\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-mukunda-software-updates wp-block-embed-mukunda-software-updates\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"Pz3pH1m1PH\"><a href=\"https:\/\/mukundasoftware.com\/blog\/help\/outlook\/what-is-normalemail-dotm-in-outlook.html\">What is NormalEmail.dotm in Outlook<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"&#8220;What is NormalEmail.dotm in Outlook&#8221; &#8212; Mukunda Software Updates\" src=\"https:\/\/mukundasoftware.com\/blog\/help\/outlook\/what-is-normalemail-dotm-in-outlook.html\/embed#?secret=dZheMfCGyS#?secret=Pz3pH1m1PH\" data-secret=\"Pz3pH1m1PH\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>TL;DR: The most common fix is re\u2011registering the AAD Broker Plugin via PowerShell. Jump straight to Solution 3 to get back into Outlook quickly. If you\u2019re staring at the error \u201cA required authentication broker is missing\u201d while trying to sign in to the Outlook desktop app, you\u2019re not alone. This issue has been frustrating Microsoft &#8230; <a title=\"Fix: \u201cA Required Authentication Broker is Missing\u201d in Outlook &amp; Microsoft 365\" class=\"read-more\" href=\"https:\/\/mukundasoftware.com\/blog\/help\/outlook\/fix-required-authentication-broker-missing-outlook.html\" aria-label=\"Read more about Fix: \u201cA Required Authentication Broker is Missing\u201d in Outlook &amp; Microsoft 365\">Read more<\/a><\/p>\n","protected":false},"author":4,"featured_media":2312,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49],"tags":[],"class_list":["post-2311","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-outlook"],"_links":{"self":[{"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/posts\/2311","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/comments?post=2311"}],"version-history":[{"count":1,"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/posts\/2311\/revisions"}],"predecessor-version":[{"id":2313,"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/posts\/2311\/revisions\/2313"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/media\/2312"}],"wp:attachment":[{"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/media?parent=2311"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/categories?post=2311"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mukundasoftware.com\/blog\/wp-json\/wp\/v2\/tags?post=2311"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}