The Custom Classes: Deny read access machine setting should be configured correctly. This policy setting denies read access to custom removable storage classes. If you enable this policy setting, read access will be denied to these removable storage classes. If you disable or do not configure this policy setting, read access will be allowed to these removable storage classes. Fix: (1) GPO: Computer Configuration\Administrative Templates\System\Removable Storage Access\Custom Classes: Deny read access (2) KEY: HKLM\Software\Policies\Microsoft\Windows\RemovableStorageDevices\Custom\Deny_Read\Deny_Read