Cannot Upload Files Simultaneously
RadUpload has been replaced by RadAsyncUpload, Telerik’s next-generation ASP.NET upload component. If you are considering Telerik’s Upload control for new development, check out the documentation of RadAsyncUpload or the control’s product page. If you are already using RadUpload in your projects, you may be interested in reading how easy the transition to RadAsyncUpload is and how you can benefit from it in this blog post. The official support for RadUpload has been discontinued in June 2013 (Q2’13), although it is still be available in the suite. We deeply believe that RadAsyncUpload can better serve your upload needs and we kindly ask you to transition to it to make sure you take advantage of its support and the new features we constantly add to it.
RadUpload cannot upload files simultaneously because when a page gets submitted, there is only a single request sent to the server.
That is why the files are uploaded one by one. As a result you cannot have two RadProgressArea controls on a page showing different information. They will show the same information because RadProgressManager reports the information to the progress areas on the page.