Ive read many solutions from different posters heres mine its very easy..
Make another folder of download directory temporary not the previous original download folder make a new one
then move all unfinished files there including the folder
go to the installation directory
C:\Program Files\BitComet\torrents
click find download again the previous torrent file thats missing trust me its there..
the task properties will show to you
click download now. then it will start to dowload again at that point within a 2-3 sec stop the download
go to your new download folder temporary as u made earlier then select move all the files back to its original download folder directory
it will say the folder contains same file blah blah blah then click yes to all to overwrite the files then close the folder
back to bitcomet right click the task select manual hash check when finished
start the download again youll see your previous download percentage will be back normally
100% working tried n tested.enjoy!
original post by me: NOR3CA