One of the worst moments is when you have deleted a file on Windows , your camera or phone and remember you need it. I recently have had the case when for some reason a micro sd card having a video I needed become unreadable.
The most viable application I have found to recover files is Recuva from Periform. In the case of the micro sd card above, I used Windows and did a quick formatted on the micro sd card and then used Recuva‘s deep scan and got my files back.
NOTE: Once a file is deleted there is no guarentee that a file can be recovered. The most siginificant factors I have experienced are device errors and the amount of activity on the device prior to trying to recover files.