I wouldn't bother too much with it. Windows doesn't use this but other
applications use it to keep track of file changes, by default this is
disabled on Windows XP installations but any application can turn it on if
it needs it.
Change Journals
http://msdn.microsoft.com/en-us/library/aa363798.aspx
On Windows 2000 this journal was enabled by default and the file system
driver (ntfs.sys) could not overcome corruption in this file, although
infrequent, damage to this file had a pesky little side effect of
rendering the disk unreadable and unmountable. Changes were made to the
Windows XP file system driver and errors in the journal are ignored by the
driver and the disk can be mounted and read even when the journal is
corrupted.
Creating, Modifying, and Deleting a Change Journal
http://msdn.microsoft.com/en-us/library/aa363877(VS.85).aspx
Fsutil usn
http://technet.microsoft.com/en-us/library/cc788042.aspx
Change Journal Records
http://msdn.microsoft.com/en-us/library/aa363803(VS.85).aspx
Keeping an Eye on Your NTFS Drives: the Windows 2000 Change Journal
Explained
http://www.microsoft.com/msj/0999/journal/journal.aspx
John