I’ve done already a single site install which was working well, but after the problem is migrating all data from buddypress, that’s why I post here. THe problem is that in database there are many references to wp_1_ table which referer to the website ID 1. I’ve tried some search and replace in the database but everything was broken. The activity stream and groups content was right but friends relations was all broken and there was lots of issues like this.
