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This page provides solutions for common problems you may encounter while working with the Telerik UI Upload component.

No files are uploaded

Solution Make sure that the action parameter is of type IEnumerable<HttpPostedFileBase> or HttpPostedFileBase.

Using HttpPostedFile does not work.

The upload of large files is impossible

By default, ASP.NET limits the size of the maximum upload to 4MB. Additionally, IIS 7 and later limits the request size to 30MB.

Solution Override these settings in the web.config file:

  1. Increase the allowed request size and execution timeout in the httpRuntime section.

        <!-- The request length is in kilobytes, execution timeout is in seconds  -->
        <httpRuntime maxRequestLength="10240" executionTimeout="120" />
  2. Increase the allowed request size for IIS 7 in the requestFiltering section.

                <!-- The content length is in bytes  -->
                <requestLimits maxAllowedContentLength="10485760"/>

Requests to ASP.NET MVC actions are blocked during upload

Solution To work around this issue:

  1. Change the controller Session State Behavior to ReadOnly or Disabled. For more information on this topic, refer to the article on concurrent requests in ASP.NET MVC.
  2. Enable request batching to reduce the number of concurrent requests.

        .Async(async => async
            .Save("Save", "Home")

The upload never ends in Safari on iOS and OSX

The issue is caused by a bug in Safari and occurs only when the Windows authentication and disabled Anonymous Authentication setting is enabled. It is reproducible with a standard <input type="file" name="file" enctype="multipart/form-data" /> HTML element in ASP.NET MVC and Web Forms applications.

Because the File Browser dialogs of the Telerik UI Editor for ASP.NET MVC rely on the Upload control, the issue might occur when uploading images and other files through them on MAC Safari.

Solution The solution solely depends on a dedicated decision by Apple about whether and when to fix this browser issue. However, you can work around it by applying the suggestions provided in the Programmatically enable or disable anonymous authentication in IIS StackOverflow thread. This means to build a separate web service for file upload with an authentication setting, such as Anonymous for Safari scenarios, and the main application authentication setting, such as Windows Authentication.

See Also

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