The history file is an essential part of the Yarn news base.  It
contains the location where each article is stored.  If the history
file becomes corrupted, some articles may become inaccessible.

The mkhist program is a utility that rebuilds the history file by
scanning the articles in the spool files in the $YARN\news directory. 
If the spool files are not corrupt, mkhist should restore the links to
every article in the news base.  To use the program, ensure the YARN
environment variable is set to the Yarn data directory, then run mkhist
with no arguments.