When installing SightMax on a Windows 2008 R2 Server, the prechat window shows the error:

The WebResource.axd handler must be registered in the configuration to process this request

This is caused by ColdFusion, specifically the wildcard (*)  handler mapping, because this handler tries to process the request first to see if the file being requested is CFML, if not then it returns the request back to IIS, which thus causes the above error.

Solution:

Please check the properties of the SightMax Virtual Directories (Applications) > Handler mappings > remove the "AboveMapperCustom" handler that has the * for a Path. After removing the handler with the wildcard path, recycle the SightMax3 application pool.

The SightMax3 application pool must be set to "Integrated".