Firefox halts at loading status and never uploads, internet explorer asks me where to save file i don't know why. Only our OSX clients can upload with Safari but our only option on Windows is Firefox or IE. It was fine before Firefox 49.
I have the same problem, but now I tried with Chrome and the upload file feature works. My main browser is Firefox so I downgraded to 48 from 49 and the upload works again.Please let me know if this fixes your problem.