diff --git a/src/Module/Admin/Site.php b/src/Module/Admin/Site.php
index af276a3f4..36e43a6df 100644
--- a/src/Module/Admin/Site.php
+++ b/src/Module/Admin/Site.php
@@ -560,7 +560,9 @@ class Site extends BaseAdmin
 			'$no_regfullname'         => ['no_regfullname', DI::l10n()->t('No Fullname check'), DI::config()->get('system', 'no_regfullname'), DI::l10n()->t('Allow users to register without a space between the first name and the last name in their full name.')],
 			'$community_page_style'   => ['community_page_style', DI::l10n()->t('Community pages for visitors'), DI::config()->get('system', 'community_page_style'), DI::l10n()->t('Which community pages should be available for visitors. Local users always see both pages.'), $community_page_style_choices],
 			'$max_author_posts_community_page' => ['max_author_posts_community_page', DI::l10n()->t('Posts per user on community page'), DI::config()->get('system', 'max_author_posts_community_page'), DI::l10n()->t('The maximum number of posts per user on the community page. (Not valid for "Global Community")')],
+			'$mail_able'              => function_exists('imap_open'),
 			'$mail_enabled'           => ['mail_enabled', DI::l10n()->t('Enable Mail support'), !DI::config()->get('system', 'imap_disabled', !function_exists('imap_open')), DI::l10n()->t('Enable built-in mail support to poll IMAP folders and to reply via mail.')],
+			'$mail_not_able'          => DI::l10n()->t('Mail support can\'t be enabled because the PHP IMAP module is not installed.'),
 			'$ostatus_enabled'        => ['ostatus_enabled', DI::l10n()->t('Enable OStatus support'), !DI::config()->get('system', 'ostatus_disabled'), DI::l10n()->t('Enable built-in OStatus (StatusNet, GNU Social etc.) compatibility. All communications in OStatus are public.')],
 			'$diaspora_able'          => $diaspora_able,
 			'$diaspora_not_able'      => DI::l10n()->t('Diaspora support can\'t be enabled because Friendica was installed into a sub directory.'),
diff --git a/view/templates/admin/site.tpl b/view/templates/admin/site.tpl
index d69d920a0..a35d1d97a 100644
--- a/view/templates/admin/site.tpl
+++ b/view/templates/admin/site.tpl
@@ -56,7 +56,15 @@
 		{{include file="field_select.tpl" field=$community_page_style}}
 		{{include file="field_input.tpl" field=$max_author_posts_community_page}}
 
-		{{include file="field_checkbox.tpl" field=$mail_enabled}}
+		{{if $mail_able}}
+			{{include file="field_checkbox.tpl" field=$mail_enabled}}
+		{{else}}
+			<div class='field checkbox' id='div_id_{{$mail_enabled.0}}'>
+				<label for='id_{{$mail_enabled.0}}'>{{$mail_enabled.1}}</label>
+				<span class="field_help" role="tooltip" id="id_{{$mail_enabled.0}}">{{$mail_not_able}}</span>
+			</div>
+		{{/if}}
+
 		{{include file="field_checkbox.tpl" field=$ostatus_enabled}}
 
 		{{if $diaspora_able}}
@@ -64,7 +72,7 @@
 		{{else}}
 			<div class='field checkbox' id='div_id_{{$diaspora_enabled.0}}'>
 				<label for='id_{{$diaspora_enabled.0}}'>{{$diaspora_enabled.1}}</label>
-				<span id='id_{{$diaspora_enabled.0}}'>{{$diaspora_not_able}}</span>
+				<span class="field_help" role="tooltip" id="id_{{diaspora_enabled.0}}">{{$diaspora_not_able}}</span>
 			</div>
 		{{/if}}
 		{{include file="field_input.tpl" field=$global_directory}}
diff --git a/view/theme/frio/templates/admin/site.tpl b/view/theme/frio/templates/admin/site.tpl
index 2432e271a..c96af9376 100644
--- a/view/theme/frio/templates/admin/site.tpl
+++ b/view/theme/frio/templates/admin/site.tpl
@@ -135,7 +135,15 @@
 						{{include file="field_select.tpl" field=$community_page_style}}
 						{{include file="field_input.tpl" field=$max_author_posts_community_page}}
 
-						{{include file="field_checkbox.tpl" field=$mail_enabled}}
+						{{if $mail_able}}
+							{{include file="field_checkbox.tpl" field=$mail_enabled}}
+						{{else}}
+							<div class="field checkbox" id="div_id_{{$mail_enabled.0}}">
+								<label for="id_{{$mail_enabled.0}}">{{$mail_enabled.1}}</label>
+								<span class="help-block" id="id_{{$mail_enabled.0}}" role="tooltip">{{$mail_not_able}}</span>
+							</div>
+						{{/if}}
+
 						{{include file="field_checkbox.tpl" field=$ostatus_enabled}}
 
 						{{if $diaspora_able}}
@@ -143,7 +151,7 @@
 						{{else}}
 							<div class="field checkbox" id="div_id_{{$diaspora_enabled.0}}">
 								<label for="id_{{$diaspora_enabled.0}}">{{$diaspora_enabled.1}}</label>
-								<span id="id_{{$diaspora_enabled.0}}">{{$diaspora_not_able}}</span>
+								<span class="help-block" id="id_{{$diaspora_enabled.0}}" role="tooltip">{{$diaspora_not_able}}</span>
 							</div>
 						{{/if}}
 						{{include file="field_input.tpl" field=$global_directory}}