BuddyPress.org

When I change the permalinks from default the categories do not work but buddypress works.
It does not update the normal .htaccess file at all when I change the permalinks and doesn’t say it’s not writeable etc.
If i change the permalinks from default the groups etc work, but not categories. When it’s on default categories work but not the groups etc.
And I cannot find the htaccess file or where any of the redirection code is handled. Thanks for any help!