Hello to everybody. I am sorry for my bad English. I face the next problem with Mozilla Firefox on Windows 10 Home: I have created a virtual classroom at http://www.wikispaces.com. In a post of this classroom, I try to upload a small jpg file (40 kilobytes). It fails (a small uploading’s icon is spinning forever). Trying to do the same upload job with other browsers results in success at once! I have to mention that Firefox worked fine till I updated to the last version and installed tiny take (https://tinytake.com/) to capture screen video and make a video with instructions to my pupils. I tried all the next things but the problem remains: I uninstalled tiny take and all its components (the problem remains). I refreshed (reset) Firefox (the problem remains). I fully uninstalled Firefox with revo uninstaller (http://www.revouninstaller.com/revo_uninstaller_free_download.html) and then I installed Firefox again (the problem remains). (My computer is clean from malware/viruses according to Avast antivirus, Malwarebytes (I performed full scans with both programs) Notice that : 1) Firefox v48.0 on Windows XP works fine. 2) Firefox v48.0 on Windows 7 works fine. I hope to help me because I prefer using Firefox than other browsers. Thank you for your help and your time.