BUE 2014 - Windows 2012 DC - System?State issues

Hi all,

I'm having some issues with BUE2014...

Backing up a system state on a domain controller... 

Job ended: 06 March 2015 at 14:20:43
Completed status: Failed
Final error: 0xe0008488 - Access is denied.

Backup- \\server1\System?State

V-79-57344-41488 - Due to one or more errors in \\ygl-hp-adc\System?State, this backup cannot be used for conversion to virtual machines, Simplified Disaster Recovery (SDR), or a complete online restore.

V-79-57344-33928 - Access Denied. Cannot backup directory \ and its subdirectories.

This is when using the domain admin credentials. 

Any ideas why this is happening?

Regards,

Dozer