Index: kernel/content/attribute_edit.php
===================================================================
--- kernel/content/attribute_edit.php	(revision 41293)
+++ kernel/content/attribute_edit.php	(working copy)
@@ -247,6 +247,29 @@
 $requireFixup = false;
 $validatedAttributes = array();
 
+// Need to detect if post_max_size has been reached. If so, all post variables are gone....
+$postMaxSize = trim( ini_get( 'post_max_size' ) );
+// post_max_size can have values like 8M which needs to be converted to bytes
+$last = strtolower($postMaxSize[strlen($postMaxSize)-1]);
+switch ( $last ) 
+{
+    case 'g':
+        $postMaxSize *= 1024;
+    case 'm':
+        $postMaxSize *= 1024;
+    case 'k':
+        $postMaxSize *= 1024;
+}
+if( ( (int) $_SERVER['CONTENT_LENGTH'] > $postMaxSize ) &&  // This is not 100% acurrate as $_SERVER['CONTENT_LENGTH'] doesn't only count post data but also other things
+    ( count( $_POST) === 0 ) )                              // Therefore we also check if request got no post variables.
+{
+    $validation['attributes'][] = array( 'id' => '1',
+                                                           'identified' => 'generalid',
+                                                           'name' => ezi18n( 'kernel/content', 'Error' ),
+                                                           'description' => ezi18n( 'kernel/content', 'The request sent to the server was too big to be accepted. You probably uploaded a file which was too big.' ) );
+    $validation['processed'] = true;
+}
+
 if ( $storingAllowed && $hasObjectInput)
 {
     // Disable checking 'is_required' flag for some actions.