Cannot open pages in sub sites with SharePoint Designer 2010

What is happening? | What the issue is?

Cannot open pages in sub sites with SharePoint Designer 2010 even if users have Design or higher permissions at the sub site level

SharePoint Designer is a powerful application that enables the rapid creation, editing and deployment of content on the SharePoint platform. As such, certain mandatory permission levels are required. You use SharePoint Designer to create and customize data sources, views and forms, workflows, master pages, and more. When performed together, you can create real business solutions on the SharePoint platform.

Points to be noted: SharePoint Designer is designed to request and use SharePoint permissions that grant the rights of managing & designing at the SharePoint site level it is not design to use the permission at a smaller granularity level such as list item level permissions...

Conclusion:

To be able to use SharePoint Designer and modify SharePoint content, an user needs to be a member of one of the following groups at the site collection level: Site Collection Administrators group, the Designers group, and Owners group.

Reference Documents:

1.   http://technet.microsoft.com/en-us/library/cc262939.aspx

2.   http://technet.microsoft.com/en-us/library/cc721640.aspx

Workarounds:

1. Give the user Design permissions to the Master Page gallery and read permission to the rest of the site.

2. Copy down the Master Page to the sub site instead of inheriting.

Finally, it seems that this issue is by designJ

If you have any queries/questions regarding the above mentioned information then please let me know. I would be more than happy to help you as well as resolves your issues J J