I am not sure at which version of Firefox my problem was first noted (I am now using 126.96.36.199) but it was several versions ago. My operating system is Windows XP Home.
I began to notice that I had duplication of Bookmark folder names (3 or 4 with the same name) and there is duplications of the bookmarks themselves from one Bookmark folder to the next with the same name in the Bookmarks Manager display. Since I wasn't really aware of it, I had begun to save specific bookmarks in one of those named bookmark folders so the contents of the same named bookmark folder while generally containing the same bookmarks as in another of the same name, there is some difference by having a bookmark or two in one of the folders and not in another. I need to know, if it is possible to repair this system to a non duplicated state and I need to know how it came about so that I can prevent this in the future if I am responsible for it.
When I just open the Bookmarks menu itself, the dropdown list of folders does not seem to show this same duplication that is seen collected togethr in the Bookmarks Manager display but checking further down in the Bookmarks menu does show further same named folders. I wasn't aware of this before. However, I have no idea whether the same number of duplicate folder names appear in the Bookmarks Manager.
I have occasionally exported a bookmark html file that I believe contains my entire set of bookmarks at that point in time and it does show the same duplication in folder names and bookmarks.
Can someone help me sort out this mess that I have gotten myself into and supply some consistent description so that I can understand what is going on?