'sys is undefined' error in telerik sitefinity 5.1

Question

I'm getting 'sys is undefined' error when I editted a content from a page. In Mozilla, Google Chrome and IE8 works correctly but IE10 doesn't support. I used css3 and html5 attributes in the page. How to do solve this?

Answer 1

There can be a lot of causes for this one:

1. Any chance that your server date is before the date you build your project? Usually sys is undefined happens when you have two servers and you deploy dlls that are build "in the future"

2. If not you can also check the following link from Telerik for the most common causes: http://blogs.telerik.com/aspnet-ajax/posts/10-03-16/common-reasons-for-the-lsquo-sys-is-undefined-rsquo-error-in-asp-net-ajax-applications.aspx (some of them may not apply to Sitefinity though).

3. Also check for rewriters that may be rewriting the Telerik.Web.UI.WebResource.axd url (go to the Net tab, click Start capturing) and see if there's a 404).