SharePoint Permissions Tip: Leave the Style Resource Readers group alone

I've spent quite a bit of time tracking down issues that all relate to permissions for the Style Resource Readers group. My number 1 permissions tip: Don't change anything to do with this group!!!

There are several ramifications when this group's permissions change, users may start reporting that they have 'Access Denied' errors trying to edit or create pages. Or if you have a structure where you want users to only be able to access a sub site and you don't give any permissions to the Root site, then they will get 'Access Denied' everywhere.

Create / Edit publishing pages

What that meant was, because SharePoint was trying to render the masterpage and page layout on either the page they wanted to edit or a new page, it couldn't because they didn't have access to them, regardless of the fact they had access to the page library.

It's a weird error to try and track down because the user will report that they still have access to create/edit items in a list, they can still see Site Settings, they still seem to have enough privelages to do it, but get an outright 'access denied' error.

Access Denied to sub sites

I had created a group just for a sub site to have view only permissions however users were reporting that they got 'Access Denied' messages. Again it turns out that although the Style Resource Readers group existing in the Root site with all authenticated users it didn't have any permissions on the Style Library document library itself, hence why access didn't work in the sub site.
Just ensure that the Master Page Gallery (Style Library) has the Style Resource Readers group as having restricted read permission on the library.