This method (loosing footage). Only use if Methods 1 and 2 fail.

and locate the CMOS battery (a silver coin cell, CR2032) and a set of jumper pins labeled CLR_CMOS , RESET , PASSWORD , or JP1 .

Modern DVRs often include a self-service reset feature via a mobile app.

Provide the serial number and the current date shown on the DVR screen to receive a one-time master code. Security Best Practices

Proceed to Method 2.