Google Chrome has removed support for the showModalDialog API with Chrome 37 and above. Microsoft Dynamics CRM will require an update to continue using Google Chrome. More information on the deprecation of this API can be found here:
There is a workaround available to continue using this API, which expires at the end of April 2015. This information is also documented in the link above. Once this API and workaround have been fully deprecated, Microsoft Dynamics CRM will require an update for users to continue using Google Chrome.
This was resolved with the latest version of Google Chrome