diff --git a/plugins/kolab_files/kolab_files.js b/plugins/kolab_files/kolab_files.js
index da5327a1..1abf913b 100644
--- a/plugins/kolab_files/kolab_files.js
+++ b/plugins/kolab_files/kolab_files.js
@@ -1462,11 +1462,23 @@ function kolab_files_ui()
   // file upload request
   this.file_upload = function(form)
   {
-    var form = $(form),
+    var i, size = 0, maxsize = rcmail.env.files_max_upload,
+      form = $(form),
       field = $('input[type=file]', form).get(0),
       files = field.files ? field.files.length : field.value ? 1 : 0;
 
     if (files) {
+      // check upload max size
+      if (field.files && maxsize) {
+        for (i=0; i < files; i++)
+          size += field.files[i].size;
+
+        if (size > maxsize) {
+          alert(rcmail.get_label('kolab_files.uploadsizeerror').replace('$size', this.file_size(maxsize)));
+          return;
+        }
+      }
+
       // submit form and read server response
       this.file_upload_form(form, 'file_upload', function(event) {
         var doc, response;
diff --git a/plugins/kolab_files/lib/kolab_files_engine.php b/plugins/kolab_files/lib/kolab_files_engine.php
index 67905b02..e48ccf8f 100644
--- a/plugins/kolab_files/lib/kolab_files_engine.php
+++ b/plugins/kolab_files/lib/kolab_files_engine.php
@@ -623,7 +623,7 @@ class kolab_files_engine
     {
         $this->plugin->add_label(
             'folderdeleting', 'folderdeleteconfirm', 'folderdeletenotice',
-            'uploading', 'attaching',
+            'uploading', 'attaching', 'uploadsizeerror',
             'filedeleting', 'filedeletenotice', 'filedeleteconfirm',
             'filemoving', 'filemovenotice', 'filemoveconfirm', 'filecopying', 'filecopynotice',
             'collection_audio', 'collection_video', 'collection_image', 'collection_document',
@@ -633,6 +633,7 @@ class kolab_files_engine
         $this->rc->output->set_pagetitle($this->plugin->gettext('files'));
         $this->rc->output->set_env('file_mimetypes', $this->get_mimetypes());
         $this->rc->output->set_env('files_quota', $_SESSION['kolab_files_caps']['QUOTA']);
+        $this->rc->output->set_env('files_max_upload', $_SESSION['kolab_files_caps']['MAX_UPLOAD']);
         $this->rc->output->send('kolab_files.files');
     }
 
diff --git a/plugins/kolab_files/localization/en_US.inc b/plugins/kolab_files/localization/en_US.inc
index 5023002c..1f6e618d 100644
--- a/plugins/kolab_files/localization/en_US.inc
+++ b/plugins/kolab_files/localization/en_US.inc
@@ -58,6 +58,7 @@ $labels['filedeleteconfirm'] = 'Are you sure you want to delete selected files?'
 $labels['filedeletenotice'] = 'File(s) deleted successfully.';
 $labels['filemovenotice'] = 'File(s) moved successfully.';
 $labels['filecopynotice'] = 'File(s) copied successfully.';
+$labels['uploadsizeerror'] = 'Maximum file size ($size) exceeded!';
 
 $labels['allfolders'] = 'search in all folders';
 $labels['fileskip'] = 'Skip';