Deny Format of Drives for Admins

Hi

We have multiple LUNs / Drives on Windows servers using as backup repositories. We removed all NTFS permissions from these drives except for System and backup works fine. Now our concern is to how to deny anyone including Admins to encrypt / format the disks (this happen before during a malware outbreak). If we get an option for this or a workaround for this issue, then it will be great.

Thanks in advance

LMS