A great "all-rounder." It has a dedicated "Video Recovery" feature that can reassemble fragmented video files, which is common in DVR overwriting cycles. PhotoRec (Free/Open Source):

The moment you realize footage is missing, pull the hard drive. DVRs are designed to overwrite the oldest footage automatically. Clone the Drive: Before running any recovery software, use a tool like Macrium Reflect

"Keygens" and "Cracks" are the primary delivery methods for Trojans. You might get your video back, but you could lose your entire PC's data to encryption in the process. No Support for Modern Codecs:

Despite the name, it is a powerhouse for video recovery. It supports deep scanning for various DVR file systems and can repair corrupt video files (MP4, MOV, AVI) during the process. Dolphin DVR Pro: