{"id":16368,"date":"2026-05-19T03:01:00","date_gmt":"2026-05-18T18:01:00","guid":{"rendered":"https:\/\/m365jp.net\/?p=16368"},"modified":"2026-05-19T03:15:32","modified_gmt":"2026-05-18T18:15:32","slug":"mc1261593-updated-outlook-improved-handling-of-disallowed-and-failed-email-reactions","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2026-05-19-mc1261593-updated-outlook-improved-handling-of-disallowed-and-failed-email-reactions","title":{"rendered":"MC1261593 | (Updated) Outlook: Improved handling of disallowed and failed email reactions"},"content":{"rendered":"<div class=\"postie-post\">\n<div>\n<hr>\n<table id=\"section\">\n<tbody>\n<tr>\n<th width=\"95%\">MC1261593 | (Updated) Outlook: Improved handling of disallowed and failed email reactions<\/th>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr>\n<table id=\"data\">\n<tbody>\n<tr>\n<th>Classification<\/th>\n<td>stayInformed<\/td>\n<\/tr>\n<tr>\n<th>Last Updated<\/th>\n<td>05\/18\/2026 17:32:02<\/td>\n<\/tr>\n<tr>\n<th>Start Time<\/th>\n<td>03\/25\/2026 23:13:26<\/td>\n<\/tr>\n<tr>\n<th>End Time<\/th>\n<td>06\/01\/2026 07:00:00<\/td>\n<\/tr>\n<tr>\n<th>Message Content<\/th>\n<td>\n<p>Updated May 18, 2026: We have updated the timeline. Thank you for your patience.&nbsp;<\/p>\n<p><b>[Introduction]<\/b><\/p>\n<p>  <\/p>\n<p>We\u2019re improving how Outlook respects the<b> x\u2011ms\u2011reactions: disallow<\/b> header in Classic Outlook for Windows. This update ensures that when reactions are disallowed, the Reactions button is correctly disabled and any failed reaction attempts are fully   reverted. This provides a more consistent and trustworthy user experience across Outlook clients and prevents user confusion.<\/p>\n<p>This message is associated with Roadmap ID <a href=\"https:\/\/www.microsoft.com\/microsoft-365\/roadmap?filters=&amp;searchterms=558442\" target=\"_blank\">  558442<\/a>.<\/p>\n<p><b>[When this will happen:]<\/b><\/p>\n<p>  <\/p>\n<ul>  <\/p>\n<li>Current Channel: This change has <b>rolled out<\/b> as part of version 2904 (build 19929).<\/li>\n<li>Monthly Enterprise Channel: This change has <b>rolled out<\/b> as part of version 2904 (build 19929).<\/li>\n<li>Semi-Annual Enterprise Channel: This change will be rolled out as part of version 2904 (build 19929).<\/li>\n<p>  <\/ul>\n<p><b>[How this affects your organization:]<\/b><\/p>\n<p>  <\/p>\n<p><b>Who is affected:<\/b><\/p>\n<p>  <\/p>\n<ul>  <\/p>\n<li>Users running Classic Outlook for Windows<\/li>\n<p>  <\/p>\n<li>Organizations that disallow email reactions using the x\u2011ms\u2011reactions: disallow header<\/li>\n<p>  <\/ul>\n<p><b>What will happen:<\/b><\/p>\n<p>  <\/p>\n<ul>  <\/p>\n<li>The Reactions button will appear grayed out when reactions are disallowed.<\/li>\n<p><img decoding=\"async\" style=\"width: 400px\" alt=\"user settings\" src=\"https:\/\/cxcs.microsoft.net\/file\/ccp\/en-us\/b8d53013-8219-48e7-b226-382782fcd23a\"><\/p>\n<p>  <\/p>\n<li>Failed reaction attempts will be automatically undone in the UI.<\/li>\n<p>  <\/p>\n<li>Users will no longer see misleading reaction states.<\/li>\n<p>  <\/p>\n<li>Behavior will be consistent across all Outlook clients.<\/li>\n<p>  <\/p>\n<li>The change is enabled by default and respects existing configurations.<\/li>\n<p>  <\/ul>\n<p><b>[What you can do to prepare:]<\/b><\/p>\n<p>  <\/p>\n<p>No action is required.<\/p>\n<p>You may optionally:<\/p>\n<ul>\n<li>Inform helpdesk staff about the improved reaction behavior to reduce potential user questions.<\/li>\n<li>Review internal documentation if you reference reaction controls or messaging headers.<\/li>\n<li>Continue using the <b>x\u2011ms\u2011reactions: disallow<\/b> header as you do today; existing configurations are fully supported.<\/li>\n<\/ul>\n<p><b>Learn more: <\/b><a href=\"https:\/\/learn.microsoft.com\/microsoft-365-apps\/outlook\/manage\/manage-outlook-reactions?view=o365-worldwide\" target=\"_blank\">Disallow reactions in Outlook | Microsoft Learn<\/a><\/p>\n<p><b>[Compliance considerations:]<\/b><\/p>\n<p>  <\/p>\n<p>No compliance considerations identified, review as appropriate for your organization.<\/p>\n<\/td>\n<\/tr>\n<tr>\n<th>Machine Translation<\/th>\n<td>\n<p>2026\u5e745\u670818\u65e5\u66f4\u65b0:\u30bf\u30a4\u30e0\u30e9\u30a4\u30f3\u3092\u66f4\u65b0\u3057\u307e\u3057\u305f\u3002\u3054\u8f9b\u62b1\u3044\u305f\u3060\u304d\u3042\u308a\u304c\u3068\u3046\u3054\u3056\u3044\u307e\u3059\u3002&nbsp;<\/p>\n<p><b>[\u306f\u3058\u3081\u306b]<\/b><\/p>\n<p>  <\/p>\n<p>Outlook\u304cClassic Outlook for Windows\u3067<b> x-ms-reactions: disallow<\/b> \u30d8\u30c3\u30c0\u30fc\u3092\u5c0a\u91cd\u3059\u308b\u65b9\u6cd5\u3092\u6539\u5584\u3057\u3066\u3044\u307e\u3059\u3002\u3053\u306e\u30a2\u30c3\u30d7\u30c7\u30fc\u30c8\u306b\u3088\u308a\u3001\u30ea\u30a2\u30af\u30b7\u30e7\u30f3\u304c\u8a31\u53ef\u3055\u308c\u306a\u3044\u5834\u5408\u3001\u30ea\u30a2\u30af\u30b7\u30e7\u30f3\u30dc\u30bf\u30f3\u304c\u6b63\u3057\u304f\u7121\u52b9\u5316\u3055\u308c\u3001\u5931\u6557\u3057\u305f\u30ea\u30a2\u30af\u30b7\u30e7\u30f3\u306e\u8a66\u307f\u3082\u5b8c\u5168\u306b\u5143\u306b\u623b\u3055\u308c\u307e\u3059\u3002\u3053\u308c\u306b\u3088\u308a\u3001Outlook\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u9593\u3067\u3088\u308a\u4e00\u8cab\u6027\u304c\u3042\u308a\u4fe1\u983c\u3067\u304d\u308b\u30e6\u30fc\u30b6\u30fc\u4f53\u9a13\u304c\u63d0\u4f9b\u3055\u308c\u3001\u30e6\u30fc\u30b6\u30fc\u306e\u6df7\u4e71\u3092\u9632\u304e\u307e\u3059\u3002<\/p>\n<p>\u3053\u306e\u30e1\u30c3\u30bb\u30fc\u30b8\u306f\u30ed\u30fc\u30c9\u30de\u30c3\u30d7ID <a href=\"https:\/\/www.microsoft.com\/microsoft-365\/roadmap?filters=&amp;searchterms=558442\" target=\"_blank\">  558442<\/a>\u306b\u95a2\u9023\u4ed8\u3051\u3089\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<p><b>[\u3044\u3064\u8d77\u3053\u308b\u304b:]<\/b><\/p>\n<p>  <\/p>\n<ul>  <\/p>\n<li>\u73fe\u884c\u30c1\u30e3\u30f3\u30cd\u30eb:\u3053\u306e\u5909\u66f4\u306f\u30d0\u30fc\u30b8\u30e7\u30f32904(\u30d3\u30eb\u30c919929)\u306e\u4e00\u90e8\u3068\u3057\u3066 <b>\u5c55\u958b<\/b> \u3055\u308c\u307e\u3057\u305f\u3002<\/li>\n<li>\u6708\u4f8b\u30a8\u30f3\u30bf\u30fc\u30d7\u30e9\u30a4\u30ba\u30c1\u30e3\u30f3\u30cd\u30eb:\u3053\u306e\u5909\u66f4\u306f\u30d0\u30fc\u30b8\u30e7\u30f32904(\u30d3\u30eb\u30c919929)\u306e\u4e00\u90e8\u3068\u3057\u3066 <b>\u5c0e\u5165<\/b> \u3055\u308c\u307e\u3057\u305f\u3002<\/li>\n<li>\u30bb\u30df\u30ca\u30a4\u30e4\u30fc\u30a8\u30f3\u30bf\u30fc\u30d7\u30e9\u30a4\u30ba\u30c1\u30e3\u30f3\u30cd\u30eb:\u3053\u306e\u5909\u66f4\u306f\u30d0\u30fc\u30b8\u30e7\u30f32904(\u30d3\u30eb\u30c919929)\u306e\u4e00\u90e8\u3068\u3057\u3066\u5c55\u958b\u3055\u308c\u307e\u3059\u3002<\/li>\n<p>  <\/ul>\n<p><b>[\u3053\u308c\u304c\u3042\u306a\u305f\u306e\u7d44\u7e54\u306b\u3069\u306e\u3088\u3046\u306a\u5f71\u97ff\u3092\u4e0e\u3048\u308b\u304b:]<\/b><\/p>\n<p>  <\/p>\n<p><b>\u5f71\u97ff\u3092\u53d7\u3051\u308b\u4eba\u7269:<\/b><\/p>\n<p>  <\/p>\n<ul>  <\/p>\n<li>Windows\u7248\u30af\u30e9\u30b7\u30c3\u30afOutlook\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u30e6\u30fc\u30b6\u30fc<\/li>\n<p>  <\/p>\n<li>x-ms-reactions: disallow \u30d8\u30c3\u30c0\u30fc\u3092\u7528\u3044\u305f\u30e1\u30fc\u30eb\u30ea\u30a2\u30af\u30b7\u30e7\u30f3\u3092\u7981\u6b62\u3059\u308b\u7d44\u7e54<\/li>\n<p>  <\/ul>\n<p><b>\u4eca\u5f8c\u306e\u5c55\u958b:<\/b><\/p>\n<p>  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<\/p>\n<li>\u3053\u306e\u5909\u66f4\u306f\u30c7\u30d5\u30a9\u30eb\u30c8\u3067\u6709\u52b9\u5316\u3055\u308c\u3066\u304a\u308a\u3001\u65e2\u5b58\u306e\u8a2d\u5b9a\u3092\u5c0a\u91cd\u3057\u307e\u3059\u3002<\/li>\n<p>  <\/ul>\n<p><b>[\u6e96\u5099\u306e\u305f\u3081\u306b\u3067\u304d\u308b\u3053\u3068:]<\/b><\/p>\n<p>  <\/p>\n<p>\u4f55\u306e\u5bfe\u5fdc\u3082\u5fc5\u8981\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<p>\u30aa\u30d7\u30b7\u30e7\u30f3\u3067\u4ee5\u4e0b\u3092\u9078\u3079\u307e\u3059:<\/p>\n<ul>\n<li>\u6539\u5584\u3055\u308c\u305f\u53cd\u5fdc\u884c\u52d5\u306b\u3064\u3044\u3066\u30d8\u30eb\u30d7\u30c7\u30b9\u30af\u30b9\u30bf\u30c3\u30d5\u306b\u77e5\u3089\u305b\u3001\u30e6\u30fc\u30b6\u30fc\u306e\u8cea\u554f\u3092\u6e1b\u3089\u3059\u3053\u3068\u3002<\/li>\n<li>\u30ea\u30a2\u30af\u30b7\u30e7\u30f3\u30b3\u30f3\u30c8\u30ed\u30fc\u30eb\u3084\u30e1\u30c3\u30bb\u30fc\u30b8\u30f3\u30b0\u30d8\u30c3\u30c0\u30fc\u3092\u53c2\u7167\u3059\u308b\u5834\u5408\u306f\u3001\u5185\u90e8\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u3092\u78ba\u8a8d\u3057\u307e\u3057\u3087\u3046\u3002<\/li>\n<li>\u4eca\u65e5\u306e\u3088\u3046\u306b <b>x-ms-reactions: disallow<\/b> \u30d8\u30c3\u30c0\u30fc\u3092\u4f7f\u3044\u7d9a\u3051\u3066\u304f\u3060\u3055\u3044;\u65e2\u5b58\u306e\u69cb\u6210\u306f\u5b8c\u5168\u306b\u30b5\u30dd\u30fc\u30c8\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/li>\n<\/ul>\n<p><b>\u8a73\u3057\u304f\u306f\u3053\u3061\u3089: <\/b><a href=\"https:\/\/learn.microsoft.com\/microsoft-365-apps\/outlook\/manage\/manage-outlook-reactions?view=o365-worldwide\" target=\"_blank\">Outlook\u306e\u30ea\u30a2\u30af\u30b7\u30e7\u30f3\u3092\u7981\u6b62\u3059\u308b|Microsoft Learn<\/a><\/p>\n<p><b>[\u30b3\u30f3\u30d7\u30e9\u30a4\u30a2\u30f3\u30b9\u4e0a\u306e\u8003\u616e\u4e8b\u9805:]<\/b><\/p>\n<p>  <\/p>\n<p>\u30b3\u30f3\u30d7\u30e9\u30a4\u30a2\u30f3\u30b9\u4e0a\u306e\u61f8\u5ff5\u4e8b\u9805\u306f\u7279\u5b9a\u3055\u308c\u305a\u3001\u7d44\u7e54\u306b\u5fdc\u3058\u3066\u30ec\u30d3\u30e5\u30fc\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>MC1261593 | (Updated) Outlook: Improved handling of disallowed and failed email reactions Classification stayI [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-16368","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/16368","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/comments?post=16368"}],"version-history":[{"count":0,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/posts\/16368\/revisions"}],"wp:attachment":[{"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/media?parent=16368"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/categories?post=16368"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/m365jp.net\/index.php\/wp-json\/wp\/v2\/tags?post=16368"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}