GZipStream not reading the whole file

I ended up using a gzip executable to do the decompression instead of a GZipStream. It can't handle the file for some reason, but the executable can.

EDIT

Try not leaving the GZipStream open:

GZipStream gzipStream = new GZipStream(fileInput, CompressionMode.Decompress,  
                                                                         false);

or

GZipStream gzipStream = new GZipStream(fileInput, CompressionMode.Decompress);