Hey Ty, bokifirefox There are some interesting things with uploads, sometimes I would assume that there is just a limit in the chunks of the file uploaded at a time. However sometimes specific sites have limits as well. And some sites use different methods.

In the past Firefox has a bug that is now fixed uploading large files so this may be difficult to troubleshoot. I would image, since there is not a client/Firefox upload limit, its the website/router etc. Ask your isp as well.

Thanks. I forgot to mention my tests were done locally (on XAMPP server). File transfers were therefore from one disk to another (or on the same), and take just several seconds or so. So it can't be the router or internet service provider. And >250MB file upload works ok in other browsers, so I am guessing the issue is specific to Firefox. I will see how it behaves in uploads to the real server. But at the moment, I have issue with uploading large files (>50-100MB) on the real server (troubleshooting now) in ALL browsers. Something in the chain: Browser-->Ajax-->Router-->ISP-->PHP settings(php.ini, .htaccess)-->Server is wrong or has limits set.

Not sure whether the following is relevant, as the issue is several months old now:

Firefox 36 changed something that has an issue in this scenario: you are posting over HTTPS and the destination uses a CISCO ACE load balancer. See:

• File Upload error with SSL
• Upgrading from 35 to 36 caused secure connection failed errors
• jquery - Firefox 36 aborts https requests with content length greater than 1778 - Stack Overflow