Chk-Back is a Windows utility that can scan the content of a .chk file created by Microsoft Chkdsk and restore the original file type for many common file types.
Chk-Back works by comparing the unique signature at the start of a file, known as the header, to an internal database of known file types. This removes the necessity to use a hexadecimal editor or trial and error to retrieve files that have been damaged in this way.
TRC Data Recovery Ltd produced Chk-back to aid in our day to day data recovery activities, but have decided that there is a wider audience to benefit from this relatively simple yet incredibly useful application. You are welcome!