Certain browsers (IE11, Chrome and Opera) have security restrictions which prevent the loading of XML files (like the one used by Juicebox to store the configuration options and image data) locally from your own computer's hard drive. Unfortunately, there is nothing that can be done to circumvent this behavior.
Please note that this happens only when trying to load galleries locally (from your own computer's hard drive) and does not happen once galleries have been uploaded to a web server.
We already have FAQs for Chrome and Opera and will add one for IE11 in the next site update. (It was previously possible to preview galleries locally in IE10 but not now in IE11.)
If you want to view your gallery on your own computer before uploading it to your website, please preview it in either Firefox or Safari.
If you see the 'Config XML Not Found' message for a gallery which has been uploaded to a web server, please see this FAQ:
When I view my gallery I see the message 'Config XML file not found'. How do I fix this?