As a last resort, many DVRs have a physical reset button or a set of "jumper pins" on the internal motherboard. Holding this button while powering on the device will usually revert all settings—including the password—back to factory defaults. Best Practices for DVR Security
Most modern DVRs allow you to set "Secret Questions." If you set these up during installation, you can reset your password directly from the login screen. Email Recovery: dvr login password
If you are looking to regain access to a DVR system because the password was lost or the device was purchased second-hand, you are likely encountering one of the many generic "admin" defaults used by OEM (Original Equipment Manufacturer) devices. Many budget DVRs are rebranded units manufactured by a handful of companies (like Dahua or Hikvision) or use similar legacy firmware. As a last resort, many DVRs have a