Common things to check when you cannot upload a file using Silverlight (Multi-file uploader)

This article describes Silverlight settings to check when trying to upload a file in the media library, and the upload dialog doesn’t load.
You can find general information about uploading multiple files at once by using the following link: File management - Uploading multiple files at once.

• The first requirement is Microsoft Silverlight needs to be installed on your computer or server.

• The second item to check is disk permissions for the ~/App_Data/CMSTemp/MultiFileUploader/ folder.  Please ensure the application pool account on which IIS is running for your site, has the correct write disk permissions as mentioned in our documentation: Disk permissions problems.

• Another item to check for your application to work correctly is, the MIME types used for Silverlight.  These are used so your web server will recognize Silverlight content appropriately.
Extension: .xaml
MIME type: application/xaml+xml

Extension: .xap
MIME type: application/x-silverlight-app

You can find an example on how to add these to IIS by using the link below:
Silverlight IIS configuration.

• In some cases when using Internet Explorer, it may be necessary to add the domain name as a trusted site in your browser. 

• Finally, you can force the system to only use the single-file uploader, by adding following key into your web.config file:
<add key="CMSUseSilverlightUploader" value="false" />


Applies to: Kentico CMS 6.x
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