How to Block CDs, DVDs, Flash Drives, and External Hard Disks
One of the biggest security problems, certainly in the corporate space, is the use of external flash drives, CDs, DVDs, and external hard disks. If not carefully vetted, these media can transfer viruses and other malware onto a computer or be used to steal information.

You can use Local Group Policy Editor to deny access to these devices for specific users or for everyone. To access Group Policy Editor, type gpedit.msc in the Start menu search box. Find the relevant settings by clicking Administrative Templates under the Computer Configuration, clicking System, and then clicking Removable Storage Access.

How to Block CDs, DVDs, Flash Drives, and External Hard Disks QI2QYuA

USB flash drives and external hard disks are classified as removable disks. To allow or deny access to a wide range of plug-in drives, right-click any of the settings, click Edit, and then click Disable to block access to the selected group of drives.