What are incomplete files?
Many users have questions about incomplete files, so I decided to write this tutorial. Here you will find some information about the causes for files being incomplete after downloading, and how you can solve this.
Why are files sometimes incomplete?
There are four possible explanations for incomplete, downloaded files. To understand these, it is important to know that files consist of multiple smaller pieces, called articles, when they are in a binary Usenet newsgroup. Normally articles aren't noticed: the newsreader downloads all small parts and puts them together in the background before saving the file to a hard disk. When a file is incomplete, one or more articles of that file are missing. One possible cause for this is that something went wrong while downloading. However, in most cases an external factor causes this problem.
As you probably know, files in Usenet newsgroups are placed by people using a program like PowerPost. People always post files to the server that they use, which is most likely an alternate server to the one that you use to download files. This is possible because news servers exchange data. The second possibility for incomplete files is that something may go wrong during the exchange of data. It is possible that the file is complete in one server, but incomplete in another one. In general pay servers have a higher completion rate than news servers of ISPs because they spend more time (and money) to increase the quality of their news server, and they receive files from multiple locations.
A third possible cause involves retention: files in binary Usenet newsgroups are not stored permanently, but are removed after a certain period of time. The length of this period differs per server. While some pay servers offer a retention of several hundreds of days, other servers may store files for just a couple of days. When files are old enough to be deleted, chances of missing articles increase.
The final explanation is the poster himself; the poster's connection may have failed or the computer may have crashed altogether.
Some of my downloaded files are incomplete! Now what?
You can use the program QuickPar to verify whether downloaded files are complete when the poster also posted a PAR2 file. You can also download extra PAR2 repair files to repair corrupt, missing and incomplete files! This is explained in our QuickPar tutorial. So fortunately you will be able to repair incomplete files when PAR2 files are available. If a lot of files seem to be incomplete, you can ask the poster for extra PAR2 files. A more permanent solution might be to acquire access to a better server, like a pay server.