There are two kinds of data calamities: hard and soft. A hard crash, where the disk has been physically damaged, requires specialist tools to recover the data - sorry, but that's not what I do. More often than not, though, the disk/Flash drive/USB stick/SD card is OK - it's the information that's stored there that is corrupt. I cannot guarantee that I will recover your data for you, but at least I will have a look. I have been writing low-level operating system software for thirty years, and know the various file systems out there back to front. I can look at the raw data on the drive and see why the Operating System cannot understand how to read the files on it. Sometimes a quick tweak to the file structure will recover swathes of files. Other times it is a laborious hunt through the gigabytes of data looking for the One True File. And, of course, sometimes the data is just gone for good. Depending on the situation, sometimes it is easiest to send me the disk/USB stick/SD card. Other times, I can guide you on the techniques necessary to extract the data so that you can upload it to me. I can then look at it online, tweak the problem area(s), and you can then write the fixed data back to the disk without having to send it anywhere.