Hi

Create 2 new directorys on your drive, "Corrupted" and "Scraps".
Cut and Paste or Drag and Drop your corrupted file into "Corrupted".
Copy the entire file name to the clipboard.
Open the Properties dialog and write down the file size ( in bytes).
Start the file tear utility
Click the button under "Source File", browse to "Corrupted", select your file, and click "Open"
Click the button under "Save Extraction...", browse to "Scraps", paste file name into "File name" field and click "Open".
Click the button under "Destination ...", browse to whatever directory your Gnucleus partials are in, paste file name into "File name" field and click "Open".
In the "Tear from..." field enter the file size, in bytes that you want to keep and try to resume from.
In the "Count" field enter the file size, in bytes that you want to remove.
The "tear from..." field and the "Count" field together, should equal the file size of your corrupted file.
Maybe someone else can tell you what the minimum amount you should remove would be. I always just trim back to an even number.
Example, corrupted file size- 123,456,789 bytes "Tear from"- 123400000 and "Count"- 56789
Click "Tear file!". When it finishes creating the new files you can delete the original corrupted file and the scrap file.

Questions? Just ask away. Good Luck.