HIKVISION Digital Video Recorder User Manual page 106

At least one record file shall be selected.
Figure 7. 33 Result of Normal Video Search for Backup
3. Backup device management.
Click Erase button if you want to erase the files from a re-writable CD/DVD.
 There must be a re-writable CD/DVD when you make this operation.
 If the inserted USB writer is not recognized:

Click the Refresh button.

Reconnect device.

Check for compatibility from vendor.
User Manual of Digital Video Recorder
Figure 7. 34 USB Writer Management
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