Many times internet connection gets dropped e.g. If you are using any router :- Many times there is surge from cable internet provider, this doesnt effect their modem but router gets effected, so internet is temporarily dropped.

But utorrent will keep on trying to download and hence fail. Tracker updates occur every 15mins or so. So after connection resumes it will take some time to get utorrent back onto downloading.

This can be expedited by rt click on torrent and select update tracker. This will result in begining of instant tracker update. So after some time download resumes.

If nothing helps. Exit from utorrent and restart it.

As per my experience xDR releases are seeded at very very fast rate so it hardly takes more than couple of hours to download 1cd rips.

Hope something helps