CRM 2013 proved a new online form(which is set by default) other then the "Information" and "Mobile" form, so if u have to map all fields and javascript again on this new form after migrating from 2011 to 2013. Or what you can do ti save time is :
1. In Account Customization -> Forms, Deactivae the new "Account" form.
2. At Record level, open a record and try changing the Form from "Account" to "Information" at the left corner of the form.
3. Also check other users security role, check if the user has enough rights on Account Entity.