Writer 4.1.4.2 in Spanish. Index Edition does not work

I am trying to format an eBook for publishing on Amazon and I’m using Writer 4.1.4.2 in Spanish. I have inserted a user index in my text and I cannot edit it now to delete duplicated titles because Help indications are uselees. No way to unprotect and delete wrong entries in my index. What can I do? Thanks for your help.

The automatically-generated indices generally should not be manually edited for content. If the undesired index entries no longer exist as sections in the document, updating the index should do the job. For this:

  1. Click anywhere in the index.
  2. Right-click and select Update Index/Table from the pop-up menu.

However, it is possible to do the manual edition of the index; for this:

  1. Click anywhere in the index.
  2. Right-click and select Edit Index/Table from the pop-up menu.
  3. Click the Index/Table tab
  4. De-select (un-check) the option Protected from manual changes.

More information on the Writer Guide, section Updating, Editing, and Deleting Indexes and Tables of Contents (en español).

I do what you say, I have unprotected the index but nothing happens when I delete the duplicate entry.
I save the new file on the same name, close Writer, open the file and the duplicate title is always there.
I imagine I must write it again.
Still a question , is it possible to have an index without page numbers ?

Have you tried creating the index anew? If the duplicate entry still occurs, you might have to check the configuration of your index or whether you have duplicate text or heading within your document. Check the Writer Guide. As for your other question, I suggest you ask it separately.

I’ll do what you say because I dont find any other possibility.
Concerning you suggestion for the other question I have already posted a separate one and it is solved.
Thanks for your help