There are following possibilities:
Explanation:
1. If Video quality setup is too low then reconfigure video quality setup.
2. If Program read error, bit data is too small. There is mosaic in the full screen. Please restart the DVR to solve this problem.
3. If HDD data ribbon error then replace ribbon.
4. If HDD malfunction then replace HDD.
5. If DVR hardware malfunctions then replace hardware.