What are you using to extract the file, and if you are sure the file is fine, why do you think this would be a Firefox issue?

.tar files are generally unknown to Windows, so the issue may be you need a proper extraction tool for it. If your intention is to download a file for serving some purpose in Windows, chances re you may need to download a Windows version instead. All this is based on the fact you posted your question using Windows, of course.

Yes , i am using windows and i think it is firefox issue because it is working on chrome fine.. i am working in ond application which is using angular 2 as a framework. And by clicking on Download button it is downloading a tar file which is located on server. So i thought it might be code issue. But if i directly paste the url in browser thn file is downloaded but same issue u am facing.