diff --git a/inc/attachments.inc.php b/inc/attachments.inc.php
index 0b1cc9aa..3f460d00 100644
--- a/inc/attachments.inc.php
+++ b/inc/attachments.inc.php
@@ -41,14 +41,16 @@ function hesk_uploadFile($i, $isTicket = true)
     global $hesk_settings, $hesklang, $trackingID, $hesk_error_buffer, $modsForHesk_settings;
 
     /* Return if name is empty */
-    $name = $_FILES['attachment']['name'][$i];
+    $name = $i == -1
+        ? $_FILES['attachment']['name']
+        : $_FILES['attachment']['name'][$i];
     if (empty($name)) {
         return '';
     }
 
 
     /* Parse the name */
-    $file_realname = hesk_cleanFileName($_FILES['attachment']['name'][$i]);
+    $file_realname = hesk_cleanFileName($name);
 
     /* Check file extension */
     $ext = strtolower(strrchr($file_realname, "."));
@@ -57,7 +59,9 @@ function hesk_uploadFile($i, $isTicket = true)
     }
 
     /* Check file size */
-    $size = $_FILES['attachment']['size'][$i];
+    $size = $i == -1
+        ? $_FILES['attachment']['size']
+        : $_FILES['attachment']['size'][$i];
     if ($size > $hesk_settings['attachments']['max_size']) {
         return hesk_fileError(sprintf($hesklang['file_too_large'], $file_realname));
     } else {
@@ -88,7 +92,9 @@ function hesk_uploadFile($i, $isTicket = true)
     if (!$isTicket) {
         $directory = $modsForHesk_settings['kb_attach_dir'];
     }
-    $file_to_move = $_FILES['attachment']['tmp_name'][$i];
+    $file_to_move = $i == -1
+        ? $_FILES['attachment']['tmp_name']
+        : $_FILES['attachment']['tmp_name'][$i];
     if (!move_uploaded_file($file_to_move, dirname(dirname(__FILE__)) . '/' . $directory . '/' . $file_name)) {
         return hesk_fileError($hesklang['cannot_move_tmp']);
     }
diff --git a/inc/view_attachment_functions.inc.php b/inc/view_attachment_functions.inc.php
index e54075b8..d238c881 100644
--- a/inc/view_attachment_functions.inc.php
+++ b/inc/view_attachment_functions.inc.php
@@ -298,7 +298,8 @@ function display_dropzone_field($url, $id = 'filedrop') {
         dictCancelUploadConfirmation: ".json_encode($hesklang['attachment_confirm_cancel']).",
         dictRemoveFile: ".json_encode($hesklang['attachment_remove']).",
         previewTemplate: $('#previews').html(),
-        clickable: '.filedropbutton-".$id."'
+        clickable: '.filedropbutton-".$id."',
+        uploadMultiple: false
     };
     </script>
     ";
diff --git a/internal-api/admin/knowledgebase/upload-attachment.php b/internal-api/admin/knowledgebase/upload-attachment.php
index c194d6df..99aeca7b 100644
--- a/internal-api/admin/knowledgebase/upload-attachment.php
+++ b/internal-api/admin/knowledgebase/upload-attachment.php
@@ -16,7 +16,7 @@ $modsForHesk_settings = mfh_getSettings();
 
 if (!empty($_FILES)) {
     // Only 1 files is ever processed through this endpoint at a time.
-    $id = upload_temp_attachment(0, false);
+    $id = upload_temp_attachment(-1, false);
     print json_encode($id);
     return http_response_code(200);
 }
diff --git a/internal-api/ticket/upload-attachment.php b/internal-api/ticket/upload-attachment.php
index 1a04fdbf..b98b982b 100644
--- a/internal-api/ticket/upload-attachment.php
+++ b/internal-api/ticket/upload-attachment.php
@@ -15,8 +15,7 @@ hesk_dbConnect();
 $modsForHesk_settings = mfh_getSettings();
 
 if (!empty($_FILES)) {
-    // Only 1 files is ever processed through this endpoint at a time.
-    $id = upload_temp_attachment(0, true);
+    $id = upload_temp_attachment(-1, true);
     print json_encode($id);
     return http_response_code(200);
 }