I am using Limewire version 4.9.23 on a Mac running OS 10.3.9.

Like midnight_blue originally reported in this Forum, this version adds an "Individually Shared Folder" as a sub-folder to the "Shared Files" folder.

While the Options window includes a "Share Finished Downloads" button in which you can supposedly turn off this feature, the button does not seem to function as one might think it should. I would have expected it to immediately make the files in its sub-folder to become not sharing. Instead, this button only appears to control all subsequent downloads you make. It does not seem to have any impact on files already in its sub-folder. (In my book, when a feature does not work as expected, it is a bug, so it would be a good idea if the developers refined this feature.)

However, there is a way around this button's current limitation. My experimenting leads me to conclude that there is no need to downgrade to a previous version, however.

While LeeWare's suggestion to go to Tools/Sharing menu does not seem to work on the Mac version, since Tools menu only leads to Statistics (there is no such menu command path that goes Tools > Sharing), the recommendation that Lord of the Rings (go Frodo!) made is actually the best fix for the present. It worked for me!

To re-state the Lord's recommendation:
...Select a file (or files) listed in the main Library window, and right-click the item (Mac users need to control-click) to generate a contextual menu that will allow you to stop sharing the selected item(s).

While you cannot summarily dismiss all of the files in the "Individually Shared Folder" by highlighting the name of that folder in the left-hand most column (because the command to "Stop Sharing Folder" will be shadowed out!), you can get a command to "Stop Sharing File" to activate if you instead highlight a file in the main Library window where the individual files (not folders!) are listed. In fact, you can select a whole group of files and stop sharing all of them in one fell swoop!

It is likely that midnight_blue neglected to try this technique on the files inside the main Library, so he reported that it did not work for him. Until the bug pertaining to the "Share Finished Downloads" button is fixed, this seems to be a viable work-around.