I noticed in my web application that I was unable to select a .csv file to upload using the AsyncUpload control when using the MS Edge browser.
I initially though that it must have been excluded by the AllowedFileExtensions property, however found that it was working using Chrome.
I am not on the latest version of the RadControls but experienced the exact same issue on the demo site below
I do have the anniversary update of Windows 10 installed and am wondering if it is related.
My version of Edge is as follows