courtesy of xuncat.
This guide is about how to change file names and still keep seeding. This feature is available in uTorrent version 1.8 (which is in beta at the time of writing) and presumably later. You can not change file names and keep seeding with earlier versions of uTorrent.
You can use this guide if you move or rename the folder in addition to changing file names. If you only want to move the folder or change its name, see the guide uTorrent: Move/rename folder and keep seeding.
It is possible to change file (and folder) names because they are not really parts of the files. They are like “labels” that tell the computer where to find the content of the files. You can not change the tags for music files and keep seeding. The tags are part of the files (headers), and changing them will make the files fail the hash check in your torrent client.
You need to rename the files outside of uTorrent, no matter if you rename each file manually or batch rename files in order to replace underscores with spaces, etc. After such changes, you need to retarget the files in uTorrent if you want to keep seeding the torrent. The procedure for doing this is the same no matter if the torrent is already loaded in uTorrent, or if you add it as a new torrent.
1. If the torrent is already loaded in uTorrent, right-click it and choose “Stop” (if it is not already stopped). If you are adding a new torrent with changed file names, make sure that you add it in stopped mode (or stop it very quickly if you fail to do this).
2. Select the torrent, then click the “Files” tab in the lower pane. (If you have no lower pane, click “Options” and check “Show detailed info”.)
3. Right-click a file and choose “Relocate…” from the menu.
4. Optional: If you have also changed the folder name, or moved the folder, you need to browse to the right folder.
5. When you are in the right folder, simply click the new file name for the file, then click “Save”. Be careful that you really choose the right file: sometimes uTorrent and Explorer show the files in different order.
You will see the changed file name in the file list in uTorrent, too:
6. Optional: When you have changed all the file names to the new names, you may want to right-click the torrent and choose “Force re-check” in order to be sure that all the files were pointed to the right new names.
7. Right-click the torrent and choose “Start” (or “Force Start” if you want to make sure the torrent does not get queued).