There are a few questions I would clarify if I were you:Does it work on another machine with IE 9, 10 or 11?Does it work on the same machine, but with a different user account logged on?Have you tried to clear the cache (or use InPrivate Modus of IE)?Have you any special settings in IE options set? (resetting all settings and security zones back to default could help)I know nothing is related to osTicket instead it's related to IE, but my guess is that it's related to IE since you said that chrome and firefox work.