If you're using a new version of DC++, and download from someone using old DC++/oDC/Valknut, you may find the download restarts from the beginning if it gets interrupted.
This won't happen if you disable "Advanced resume using TTH" in Settings>Advanced.
well the new DC version has added yet another bug..
the current twofo server software doesnt recognise the new connection types made by the newest version of DC++ (0.68)... I recommend everyone to not upgrade to 0.68 till the server software has been updated