diff --git a/application/MantisBT/Exception/Issue/Tag/TagNotAttached.php b/application/MantisBT/Exception/Issue/Tag/TagNotAttached.php
new file mode 100644
index 0000000000..39866c81ac
--- /dev/null
+++ b/application/MantisBT/Exception/Issue/Tag/TagNotAttached.php
@@ -0,0 +1,13 @@
+<?php
+namespace MantisBT\Exception\Issue\Tag;
+use MantisBT\Exception\ExceptionAbstract;
+
+require_api('lang_api.php');
+
+class TagNotAttached extends ExceptionAbstract {
+	public function __construct() {
+		$errorMessage = lang_get(ERROR_TAG_NOT_ATTACHED, null, false);
+		parent::__construct(ERROR_TAG_NOT_ATTACHED, $errorMessage, null);
+		$this->responseCode = 400;
+	}
+}
diff --git a/application/core/tag_api.php b/application/core/tag_api.php
index f135e1ab0c..71ae924207 100644
--- a/application/core/tag_api.php
+++ b/application/core/tag_api.php
@@ -40,6 +40,7 @@
 
 use MantisBT\Exception\Database\ColumnNotFound;
 use MantisBT\Exception\Issue\Tag\TagAlreadyAttached;
+use MantisBT\Exception\Issue\Tag\TagNotAttached;
 use MantisBT\Exception\Tag\TagNameInvalid;
 use MantisBT\Exception\Tag\TagNameNotUnique;
 use MantisBT\Exception\Tag\TagNotFound;
@@ -535,7 +536,7 @@ function tag_bug_get_row( $p_tag_id, $p_bug_id ) {
 
 	$t_row = db_fetch_array( $result );
 	if( !$t_row ) {
-		trigger_error( TAG_NOT_ATTACHED, ERROR );
+		throw new TagNotAttached();
 	}
 	return $t_row;
 }
@@ -646,7 +647,7 @@ function tag_bug_detach( $p_tag_id, $p_bug_id, $p_add_history = true, $p_user_id
 	}
 
 	if( !tag_bug_is_attached( $p_tag_id, $p_bug_id ) ) {
-		trigger_error( TAG_NOT_ATTACHED, ERROR );
+		throw new TagNotAttached();
 	}
 
 	$t_tag_row = tag_bug_get_row( $p_tag_id, $p_bug_id);