Open bookmark.htm (typically located in C:\Program Files\Netscape\Users\profile name\) in Notepad. Change something insignificant that is NOT enclosed in < > (such as the title of a bookmark). Save the file and exit Notepad. The next time you start Netscape, it will notice that you have tampered with the bookmark file and rebuild it.

If you still receive an illegal operation error when starting Netscape, the bookmark file may be corrupt beyond repair. In that case, rename bookmark.htm. Netscape will create a new bookmark file the next time you start the browser.

Fortunately, Netscape saves bookmarks in an HTML-formatted web page. You can always open the old bookmark file inside Netscape (File menu--Open... or just drag and drop), visit each link, and add it to your bookmarks inside Netscape (Ctrl+D).