Consider the following scenario:
You browse to the Site Contents page for your OneDrive for Business site.
You click add an app, and then you select Document Library.
When you view the permissions for the new library, you notice that the library is shared with the Everyone except external users group.
To remove permissions for the Everyone except external users group from the document library, follow these steps:
Browse to the document library, click the LIBRARY tab, and then click Shared With.
In the share window, click ADVANCED.
Click Stop Inheriting Permissions, and then click OK.
Select the check box next to Everyone except external users, click Remove User Permissions, and then click OK.
This problem occurs because the document library inherits permissions from the parent site. This provides access to the site itself for the Everyone except external users group. By default, the OneDrive for Business library uses unique permissions and doesn't experience this behavior.
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