"IF" you know for sure that when you were recording whatever this effect was not showing on the LCD, and that when you now put the camcorder in the mode ready to shoot, that the image you see on the LCD of whatever the lens is pointing at is perfect, then that indicates that the video head requires cleaning. Slightly dirty heads can cause small square patches on the recorded image, and it either happen during recording or on playing back. Unfortunately full cleaning info cannot be sent except to a Direct e-mail address (you having restricted yours) as it contains a JPEG attachment.