What did you use to create those CSV bookmark backups? Can't you use that to restore that backup file?

Firefox bookmark backup files are in the JSON format and bookmark export file are in the HTML format. Firefox itself doesn't use CSV files for bookmarks, although extensions for Firefox may.

I am not sure I opened them in Libre Office originally. I guess there is no way to do it? Will they import into IE11, I don't use it but I can temporarily use it.

Not sure this will help you, but it's all I can think of - seeing that you think it's a bookmarks file, but it's a not familiar format.

Can you open that file in LibreOffice and then save it again in HTML format?

This header needs to be at the the top of a HTML file that is named bookmarks.html so that Firefox will recognize that file to be able to Import it as a "bookmarks" file. <!DOCTYPE NETSCAPE-Bookmark-file-1>

Nope. It only goes to a bookmark I have created this morning. Win 10 crashed my computer with the anniversary issue. I may just go back to Win 7 anyway.

Thanx