This tool will generate a daily password that reset the Dahua master password. You just need to run the password generator and enter the actual DVR date to get a new password (the date you see on the screen).
However, this method works for older Dahua DVRs/NVRs, it no longer works on the new Dahua recorders since they run a revamped firmware. If you lost the admin password for an old Dahua DVR you can use a password generator to reset it. Read this article for other methods on how to reset the master/admin password for Dahua recorders.
Download the Dahua daily password generator on this link (google drive link).
Note: This password generator works for Dahua and their OEMs sold under these brands: Activecam, Advidia, Amcrest, Ameta, Ascendent, Backstreet Surveillance, BV Security, CCTV Security Pros, CCTV Star, CP Plus (Orange Line), Dax Networks, eLine, ENS (formerly Eastern CCTV and SavvyTech), Expose, Lorex, GSS, Honeywell, IC Realtime, Ikegami, Impath Networks, Inaxsys, IndigoVision, Infinity CCTV, Innekt, Intelbras, KBVision, Lumixen, Maxron, Montavue, Oco, Optiview, Rhodium, RVI, Saxco, Security Camera King (Elite), Space Technology, Speco, ToughDog, Tyco Holis, Tyco Illustra Essentials, Unisight, VIP Vision, Watchnet, Winic, Zuum.