Currently the only plugin known to be incompatible with BP Profile Search is BuddyPress Friends On-Line version 0.4.3.1. When BuddyPress Friends On-Line is activated, all your searches will return the whole members directory.

I’ve informed the author, but if you want to fix the conflict yourself, you can apply the following changes.

1. Open the file bp-friends-on-line.php

2. Locate the function fol_get_online

function fol_get_online($data, $params){
    extract( $params, EXTR_SKIP );
    if(bp_is_user_friends() && bp_is_current_action( 'online') ){
        $type    = 'online';
        $user_id = bp_loggedin_user_id();
    }
    return BP_Core_User::get_users( $type, $per_page, $page, $user_id, $include, $search_terms, $populate_extras, $exclude, $meta_key, $meta_value );
}

3. Replace it with this new code

function fol_get_online($data, $params){
    extract( $params, EXTR_SKIP );
    if(bp_is_user_friends() && bp_is_current_action( 'online') ){
        $type    = 'online';
        $user_id = bp_loggedin_user_id();
	return BP_Core_User::get_users( $type, $per_page, $page, $user_id, $include, $search_terms, $populate_extras, $exclude, $meta_key, $meta_value );
    }
    return $data;
}

4. Save the file and confirm that BP Profile Search is now working correctly.