Transmission autochecking if I have all pieces to a file

[tacocat]

How do I stop this? I do not have the harddrive space to keep double copies of files so I can retag them to my liking, but I would like to be able to seed what I don't change. This is usually still 95%+ of the torrent. However, randomly when I shut down transmisison it will recheck the files I have and start downloading them all over again. This is a huge pain and I'd like to stop it. It also deletes what I have so it can finish it. I can't just remove the torrent and not let it download, because once it has checked for files, it removes what it doesn't like. Anyone able to tell me how to shut off this autocheck feature?

[livings124]

If you modify a file, it needs to recheck - otherwise you will upload corrupt data.