Opening SharePoint designer in production farm is generally not recommended because of huge performance hit. A power user having access to edit pages, open pages in designer may start SharePoint designer in production farm that may result in lot of performance hit. This post describes the steps how you can disable SharePoint designer for a particular web application in your production farm.
Step1: Browse SharePoint Central Administration and go to Application Management
Step2: Click on Manage Web Applications link
Step3: Select a particular web application for which SharePoint designer need to be disabled and then click on General setting drop down menu
Site collection administrator can also disable the SharePoint designer setting from the Site Settings page as shown below
Step4: Click on SharePoint Designer from the General settings menu, uncheck the checkbox “Enable SharePoint Designer” as shown below
SharePoint designer can be enabled/disable by checking the “Enable SharePoint Designer” check box.
Once SharePoint designer is disabled for the web application, a user would see following message when trying to edit the page in SharePoint designer