Hello Paul Herzberg,
If you download a compressed file and RadCompression is not disabled for the handler in question, it is very likely that the browser gets confused because of the second compression header being added to the response. I would suggest that you manually exclude from compression the handlers used for file downloading files. The other option is to use only regular postbacks to download files and stop the Postback compression feature of RadCompression
I hope this helps.
the Telerik team
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