I am most of the way through creating a duplicate of my live site locally. (This will be a development sandbox.) I am running WordPress with Network and BuddyPress.
I started by installing XAMPP and setting my hosts file so that testsite.com points at the folder WordPress is installed in locally.
Next I imported the existing live-site database and manually updated the wp_blogs, wp_site, wp_x_options, wp_sitemeta to testsite.com instead of site.com (the live site.) wp_config.php is also updated to reflect testsite.com
At this point everything on the local site works EXCEPT the main page. I can navigate through the admin pages, and I can visit any sub-page. The automatic menu links are formed properly with testsite.com/whatever ... it's all good.
EXCEPT when I try to go to http://testsite.com it always redirects to http://site.com This happens whether I type in the address, click on the link in admin, or click on the "home" menu item from a page in the site.