When it isn't possible to automatically log into a website, for example due to multi-factor authentication, captcha requests or JavaScript requirements, you can use a web browser to login. When this option is set, WebCopy will display a browser window when a crawl action is started. You can use this window to authenticate with the website, and the associated cookies will then be used by the crawl.
This process uses Internet Explorer and cookies will be shared between WebCopy and your operating system.