Master Page and Page Layouts not available in SharePoint Designer Left Navigation (Object's Panel)

If you could open the site in SharePoint Designer but "Master Pages" and "Page Layouts" option is not available in Left Navigation(also called Object's Panel), there could be multiple reasons for that.

Lets troubleshoot this :

First thing to check: Permissions:
You need at least Designer rights on the site to do this. Click here to learn how to to check permissions in SharePoint and learn more about SharePoint permissions.

Second Thing to check : Publishing Feature:
Page Layout specifically are available in Publishing sites only. Which means that publishing feature should be activated on the site.

How to check Feature

From site setting , go to Site Features. Look for Publishing feature and activate if not activated already.

Third Thing to check Designer setting in Site Collection Settings :
SharePoint designer options could be made available or unavailable at site collection level if enabled from web application. Click here to check options.


Forth thing to check Designer settings in Central Admin:
SharePoint Designer is enabled at Web application level through Central Admin and there are options to enable partial designer options only.

Please make sure that "Enable Customizing Master Page and Page Layouts" is enabled for your web application.

Click here to know about SharePoint Designer Settings in Central Admin.