First, make sure the videos are not locked. Look at the camera display, where the key icon indicates if the files are locked. If they are locked, it is likely that the sensitivity of the G-Sensor is too high and the camera has locked the recordings, for example, due to driving over bumps. The G-sensor’s sensitivity can be altered in the menu. Should the recordings be unlocked and the camera still won’t delete old recordings, then the firmware should be updated. This, including instructions, can be downloaded from the product pages on our website. Please contact our customer service should you have any difficulties.