IIS 7 “there was an error while performing this operation”. Filename: \\?\C:\inetpub\wwwroot\
You won’t be able to open the handermappings application for this website either.
This typically occurs when plugin information is being used in the web.config file that is not installed in IIS. In most cases this is due to the missing plugin “URL Rewrite”.
To correct this simply install the missing plugin/module.
You can install this via the Web Platform Installer: https://www.microsoft.com/web/downloads/platform.aspx
Or download and install the module from http://www.iis.net/downloads/microsoft/url-rewrite#additionalDownloads