intech wrote:i have a DVR HDD (1TB), in which the date 24.6.2015 records starts from 5pm and it ends on 15.7.2015
How did you find out the available dates range? If the drive and the unit itself are OK and you checked that using some internal means, then not much can be done, unfortunately.
DVR recordings are looped and the oldest ones are getting overwritten once the drive is full.
According to our experience with DVRs, it could be possible to recover an extra 1%, which may appear gone due to a different algorithm imperfections.
In rare cases this number can go up to 2, maybe 3%, as some models add gaps between groups of frames and something can be there, but that's more of a luck than technology.