VKExtract is a free software which allows you to backup your messaging history from VK to your PC, exporting it to the HTML documents with resources.
It supports multiselection, forwarded messages and some other attachments. This app allows you to make the most full backup of your messages.
Also, it marks time of first and last message, count of all messages, and some other. It builds a HTML file of page when loaded all dependencies and messages. It can show progress of each of them: completed dialogs, messages of dialog, attachments of message and even attachment downloading progress.
You can download it here:
Dialog extractor window: