Could you confirm that you are overriding (resetting) the TemporaryFolder property of the Custom Handler as follows:
"Custom UNC path"
TemporaryFolder = value;
1. Under Firefox and Chrome the RadAsyncUpload control is using FileApi module to upload files. The module is uploading files on chunks (2MB each). Because of the ASP.NET framework limitation - 4MB maximum on request. The only thing (without impersonation limitation) to make the RadAsyncUpload control work is to upload the files into a shared folder.
2. When using FileApi module the Process method of the Handler is executed after the file is assembled. In case that you are using IFrame module the file is sent as an entity and you have a direct reference to it.
We are aware of that limitation and we are going to resolve it for the next releases. To avoid duplication of the threads, please let us continue our discussion in only one of them.
the Telerik team
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