The Internet News Service creates a file called the Ics.dat file that is located in the Insdata directory. If the Ics.dat file is corrupted or lost, the Internet News Service creates a new Ics.dat file. During the next NNTP connection, the Internet News Service attempts to replicate all the messages in the newsgroup public folders included in the newsfeed. To prevent this from occurring, choose Mark All as Delivered in the Advanced property page for that newsfeed.