Our DVR can't support the external hard drive, you need to buy an internal hard drive(3.5 inch) to install. (Like Sumsung, Seagate or Western Digital (purple))
Note: The max hard drive size supported by our DVR system is 6TB.
We suggest you buy Seagate 500GB or 1TB hard drive.
You can follow up the below video to install and format the hard drive:
Some related problems for your reference:
If this can't help you, please feel free to contact us.