Index: reference/light-blue/lib/jquery.fileupload-ui.js
===================================================================
diff -u -rb4c7602da277ecbcf0a817ee6e3ff33bb607376b -r2a8d742a4fb80aad159c11668882f02590c54b99
--- reference/light-blue/lib/jquery.fileupload-ui.js	(.../jquery.fileupload-ui.js)	(revision b4c7602da277ecbcf0a817ee6e3ff33bb607376b)
+++ reference/light-blue/lib/jquery.fileupload-ui.js	(.../jquery.fileupload-ui.js)	(revision 2a8d742a4fb80aad159c11668882f02590c54b99)
@@ -172,6 +172,7 @@
                     });
                 } else {
                     if (files.length) {
+                        files = files.filter(file => file !== null);
                         $.each(files, function (index, file) {
                             if (data.maxNumberOfFilesAdjusted && file.error) {
                                 that._adjustMaxNumberOfFiles(1);