{"id":5547,"date":"2026-06-23T10:49:54","date_gmt":"2026-06-23T10:49:54","guid":{"rendered":"https:\/\/www.mailsdaddy.com\/blogs\/?p=5547"},"modified":"2026-06-23T10:54:59","modified_gmt":"2026-06-23T10:54:59","slug":"0x80040154-class-not-registered-error-complete-fix","status":"publish","type":"post","link":"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/","title":{"rendered":"0x80040154 Class Not Registered Error \u2013 Complete Fix"},"content":{"rendered":"<p>Microsoft Outlook users may occasionally encounter the <strong>0x80040154 \u2013 Class Not Registered Error<\/strong>, which prevents Outlook from launching properly or causes issues while sending and receiving emails. This error is generally associated with damaged Outlook components, incorrect registry entries, corrupted profiles, or faulty Office installations.<\/p>\n<p>In this article, we will explain the causes of the <strong>0x80040154 Outlook error<\/strong> and provide effective methods to resolve it quickly.<\/p>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#What_is_the_0x80040154_%E2%80%93_Class_Not_Registered_Error\" >What is the 0x80040154 \u2013 Class Not Registered Error?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Common_Causes_of_Outlook_Error_0x80040154\" >Common Causes of Outlook Error 0x80040154<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Methods_to_Fix_0x80040154_%E2%80%93_Class_Not_Registered_Error\" >Methods to Fix 0x80040154 \u2013 Class Not Registered Error<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_1_Restart_Your_Computer\" >Method 1: Restart Your Computer<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_2_Run_Outlook_in_Safe_Mode\" >Method 2: Run Outlook in Safe Mode<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Steps\" >Steps:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_3_Repair_Microsoft_Office\" >Method 3: Repair Microsoft Office<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Steps-2\" >Steps:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_4_Create_a_New_Outlook_Profile\" >Method 4: Create a New Outlook Profile<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Steps-3\" >Steps:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_5_Re-register_Outlook_Components\" >Method 5: Re-register Outlook Components<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Steps-4\" >Steps:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_6_Run_System_File_Checker\" >Method 6: Run System File Checker<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Steps-5\" >Steps:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_7_Update_Microsoft_Office\" >Method 7: Update Microsoft Office<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Steps-6\" >Steps:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_8_Repair_Corrupted_PST_File_Using_ScanPST\" >Method 8: Repair Corrupted PST File Using ScanPST<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Steps-7\" >Steps:<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Method_9_Convert_OST_File_to_PST\" >Method 9: Convert OST File to PST<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Frequently_Asked_Questions\" >Frequently Asked Questions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/www.mailsdaddy.com\/blogs\/0x80040154-class-not-registered-error-complete-fix\/#Conclusion\" >Conclusion<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"What_is_the_0x80040154_%E2%80%93_Class_Not_Registered_Error\"><\/span>What is the 0x80040154 \u2013 Class Not Registered Error?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The <strong>0x80040154 error<\/strong> is a Windows COM (Component Object Model) error that appears when Outlook or another Microsoft Office application tries to access a required component that is either missing, unregistered, or corrupted.<\/p>\n<p>The error message may appear as:<\/p>\n<p><strong>&#8220;Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))&#8221;<\/strong><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Common_Causes_of_Outlook_Error_0x80040154\"><\/span>Common Causes of Outlook Error 0x80040154<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Understanding the root cause helps in selecting the right solution. Some common reasons include:<\/p>\n<p><strong>1. Corrupted Microsoft Office Installation:<\/strong> Incomplete updates or damaged Office files can prevent Outlook components from registering correctly.<\/p>\n<p><strong>2. Damaged Windows Registry Entries:<\/strong> Incorrect registry modifications may remove or alter Outlook-related COM registrations.<\/p>\n<p><strong>3. Corrupt Outlook Profile:<\/strong> A damaged Outlook profile can trigger various startup and synchronization errors, including 0x80040154.<\/p>\n<p><strong>4. Missing DLL Files:<\/strong> Required Outlook or Office DLL files may become corrupted or unregistered.<\/p>\n<p><strong>5. Third-Party Add-ins Conflicts:<\/strong> Faulty Outlook add-ins can interfere with Outlook startup processes.<\/p>\n<p><strong>6. Corrupted PST or OST Files:<\/strong> If Outlook data files become damaged, Outlook may fail to access required objects and display the Class Not Registered error.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Methods_to_Fix_0x80040154_%E2%80%93_Class_Not_Registered_Error\"><\/span>Methods to Fix 0x80040154 \u2013 Class Not Registered Error<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Follow the solutions below in order until the problem is resolved.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_1_Restart_Your_Computer\"><\/span>Method 1: Restart Your Computer<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Before applying advanced fixes, restart your system.<\/p>\n<p>A simple reboot can reload Windows services and register temporary components correctly.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_2_Run_Outlook_in_Safe_Mode\"><\/span>Method 2: Run Outlook in Safe Mode<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Safe Mode launches Outlook without add-ins.<\/p>\n<h4><span class=\"ez-toc-section\" id=\"Steps\"><\/span>Steps:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li>Press <strong>Windows + R<\/strong><\/li>\n<li>Type: <code style=\"font-style: inherit; font-weight: inherit;\">outlook.exe \/safe<\/code><\/li>\n<\/ol>\n<ol start=\"3\">\n<li>Click <strong>OK<\/strong><\/li>\n<\/ol>\n<p>If Outlook opens successfully, disable suspicious add-ins:<\/p>\n<ul>\n<li>Go to File \u2192 Options \u2192 Add-ins<\/li>\n<li>Select COM Add-ins<\/li>\n<li>Click Go<\/li>\n<li>Disable unwanted add-ins<\/li>\n<li>Restart Outlook normally<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Method_3_Repair_Microsoft_Office\"><\/span>Method 3: Repair Microsoft Office<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Repairing Office can restore missing or damaged Outlook components.<\/p>\n<h4><span class=\"ez-toc-section\" id=\"Steps-2\"><\/span>Steps:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li>Open Control Panel<\/li>\n<li>Click Programs and Features<\/li>\n<li>Select Microsoft Office<\/li>\n<li>Click Change<\/li>\n<li>Choose Quick Repair<\/li>\n<li>If needed, perform Online Repair<\/li>\n<\/ol>\n<p>After completion, restart your computer and check Outlook.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_4_Create_a_New_Outlook_Profile\"><\/span>Method 4: Create a New Outlook Profile<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>A corrupted Outlook profile is a common reason for Outlook-related errors.<\/p>\n<h4><span class=\"ez-toc-section\" id=\"Steps-3\"><\/span>Steps:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li>Open Control Panel &gt;&gt; Click Mail<\/li>\n<li>Select Show Profiles &gt;&gt; Click Add<\/li>\n<li>Create a new profile &gt;&gt; Configure your email account<\/li>\n<li>Set the new profile as default<\/li>\n<\/ol>\n<p>Launch Outlook again and verify whether the issue is resolved.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_5_Re-register_Outlook_Components\"><\/span>Method 5: Re-register Outlook Components<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Missing COM registrations can trigger the Class Not Registered error.<\/p>\n<h4><span class=\"ez-toc-section\" id=\"Steps-4\"><\/span>Steps:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li>Open Command Prompt as Administrator.<\/li>\n<li>Navigate to the Office installation directory.<\/li>\n<li>Run Outlook registration command: <code style=\"font-style: inherit; font-weight: inherit;\">outlook.exe \/regserver<\/code><\/li>\n<\/ol>\n<p>This command re-registers Outlook components in Windows.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_6_Run_System_File_Checker\"><\/span>Method 6: Run System File Checker<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Corrupted Windows system files may also generate the 0x80040154 error.<\/p>\n<h4><span class=\"ez-toc-section\" id=\"Steps-5\"><\/span>Steps:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li>Open Command Prompt as Administrator.<\/li>\n<li>Execute: <span style=\"background-color: #f2f4f5; color: #222222; font-family: Monaco, Consolas, 'Andale Mono', 'DejaVu Sans Mono', monospace; font-size: 1em; font-style: normal; font-weight: normal;\">sfc \/scannow<\/span><\/li>\n<\/ol>\n<ol start=\"3\">\n<li>Wait for the scan to complete.<\/li>\n<li>Restart the system.<\/li>\n<\/ol>\n<p>Windows will automatically repair damaged system files.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_7_Update_Microsoft_Office\"><\/span>Method 7: Update Microsoft Office<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Using outdated Office versions can cause compatibility problems.<\/p>\n<h4><span class=\"ez-toc-section\" id=\"Steps-6\"><\/span>Steps:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li>Open Outlook<\/li>\n<li>Go to File \u2192 Office Account<\/li>\n<li>Select Update Options<\/li>\n<li>Click Update Now<\/li>\n<\/ol>\n<p>Install all available updates and restart Outlook.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_8_Repair_Corrupted_PST_File_Using_ScanPST\"><\/span>Method 8: Repair Corrupted PST File Using ScanPST<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>If the error occurs due to damaged PST files, Microsoft&#8217;s Inbox Repair Tool can help.<\/p>\n<h4><span class=\"ez-toc-section\" id=\"Steps-7\"><\/span>Steps:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li>Locate ScanPST.exe<\/li>\n<li>Browse and select the PST file<\/li>\n<li>Click Start<\/li>\n<li>Repair detected issues<\/li>\n<li>Open Outlook again<\/li>\n<\/ol>\n<p>However, ScanPST may not repair severely corrupted PST files.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Method_9_Convert_OST_File_to_PST\"><\/span>Method 9: Convert OST File to PST<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>In Exchange, Office 365, or IMAP environments, OST file corruption can also trigger Outlook errors. If the OST file becomes inaccessible or Outlook cannot synchronize mailbox data, converting the OST file into PST format is often the safest solution. A professional <strong>OST to PST Converter<\/strong> can recover emails, contacts, calendars, tasks, journals, and attachments from inaccessible OST files while preserving the original folder hierarchy. <span style=\"font-size: 16px;\">MailsDaddy OST to PST Converter offers a professional and reliable way to recover mailbox data and regain access to Outlook emails without data loss. It is is designed to <span class=\"zlAe0W_TextBase zlAe0W_Text rFU14q_Emphasis\" data-w-component=\"bold\" data-w-weight=\"semibold\" data-w-inline=\"\">recover and convert inaccessible, orphaned, or corrupted OST files into PST format<\/span> while preserving the original folder hierarchy, email formatting, attachments, contacts, calendars, tasks, and other mailbox items.<\/span><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Frequently_Asked_Questions\"><\/span>Frequently Asked Questions<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><strong>1: What does Outlook Error 0x80040154 mean?<\/strong><\/p>\n<p>The error indicates that Outlook cannot access a required COM component because it is missing, damaged, or not properly registered in Windows.<\/p>\n<p><strong>2: Can corrupted PST files cause 0x80040154?<\/strong><\/p>\n<p>Yes. Damaged PST files can prevent Outlook from accessing mailbox data and may trigger this error.<\/p>\n<p><strong>3: How do I fix Class Not Registered in Outlook?<\/strong><\/p>\n<p>You can repair Office, create a new Outlook profile, run Outlook in Safe Mode, re-register Outlook components, repair PST files, or update Office.<\/p>\n<p><strong>4: Is reinstalling Outlook necessary?<\/strong><\/p>\n<p>Not always. Most users can resolve the issue through Office repair, profile recreation, or data file repair without reinstalling Outlook.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Conclusion\"><\/span>Conclusion<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The <strong>0x80040154 \u2013 Class Not Registered Error<\/strong> in Outlook usually occurs due to corrupted Office components, damaged Outlook profiles, faulty registry entries, or inaccessible PST and OST files. By following the troubleshooting methods discussed above, you can effectively restore Outlook functionality and eliminate the error.<\/p>\n<p>If the problem is linked to a damaged Outlook data file, repairing the PST file or converting an inaccessible OST file to PST can help recover important mailbox data without data loss. Regular maintenance and backups can significantly reduce the chances of encountering Outlook errors in the future.<\/p>\n<p><strong>Also Read: <a href=\"https:\/\/www.mailsdaddy.com\/blogs\/how-to-fix-0x80040600-unknown-error-in-outlook-data-file\/\" rel=\"bookmark\">How to Fix 0x80040600 \u2013 Unknown Error in Outlook Data File<\/a><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Microsoft Outlook users may occasionally encounter the 0x80040154 \u2013 Class Not Registered Error, which prevents Outlook from launching properly or causes issues while sending and receiving emails. This error is generally associated with damaged Outlook components, incorrect registry entries, corrupted profiles, or faulty Office installations. In this article, we will explain the causes of the [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":5548,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[320],"tags":[],"class_list":["post-5547","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-outlook-error"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>0x80040154 Class Not Registered Error \u2013 Complete Fix | MailsDaddy Official Blog<\/title>\n<meta name=\"description\" content=\"Learn how to fix Outlook 0x80040154 Class Not Registered Error with proven solutions. 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