Please asure to download only updates from https://www.opensource-socialnetwork.org/download
The latestest currently available release is 4.6. And if anyone else is offering 4.7 for download, simply keep away - as there are all kind of strange things expected to happen.
It is strange when I have update OSSN to 4.7 version, this component disappeared. I deleted and installed once again but it does not work anyway
In folder \components\OssnSearch\locale
Open ossn.en.php or ossn.fr.php and add:
'com:ossn:site:members' => 'Nos Membres',
@David, You have to install using component installer and then enable it by going to components page.