All this does is reload all the js/css/html files. All I can think of is that you uploaded e.g. a new version and their cache does not find the new updated files and is still looking at the old ones. I always use ABM.AppVersion = DateTime.now (in ABMApplication, Initialize) to ensure it will even reload on every restart of the the jar in the users browser. Never had a problem with it if I use this, and we have a lot of users.