I am trying to download a support app (FastViewer, "Fastclient.....exe) for getting support with an App I use for work. Problem is that the file I download does not open - both from firefox and from the downloads folder directly. Long story short, I figured out that the file was blocked when opening its properties and seeing the message that "the file is from another computer", where I could also allow it. What I tried: - Test with Chrome and Internet Explorer -> No issue - Clear Webpage data, cookies and caches -> Same issue - Refresh Firefox (https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings) -> Same issue - Try opening the affected file from another User -> Same issue - Try in another user and on another PC with firefox -> No issue - Uninstall firefox, delete all folders in the Users AppData folder (Local, Roaming and LocalLow the "Mozilla" folder), then reinstall ->Same issue ( I did not import old Data back) - Checked security settings and settings in general but did not find anything. - I tried downloading any other files (paint.net, irfanview) and all of them worked without issue. It cant be something that the webpage does, since it works in any other user and on any other PC I tested this, it is something specifically in this users Firefox Settings that is the issue. Anybody any ideas?