diff --git a/config/alfresco/templates/webscripts/org/alfresco/repository/upload/upload.post.js b/config/alfresco/templates/webscripts/org/alfresco/repository/upload/upload.post.js
index eaa7e78fa3..b925db5728 100644
--- a/config/alfresco/templates/webscripts/org/alfresco/repository/upload/upload.post.js
+++ b/config/alfresco/templates/webscripts/org/alfresco/repository/upload/upload.post.js
@@ -114,6 +114,8 @@ else
                upload = destNode.createFile(filename) ;
                upload.properties.contentType = contentType;
                upload.properties.content.write(content);
+               // reapply mimetype as upload may have been via Flash - which always sends binary mimetype
+               upload.properties.content.guessMimetype(filename);
                upload.properties.content.encoding = "UTF-8";
                upload.properties.title = title;
                upload.properties.description = description;