I can't make it work whatever I do.
I am using wp 3.2.1 and activated the Network option.
I followed these instructions: http://wordpress.org/extend/plugins/cimy-user-extra-fields/installation/ for MultiSite option #1 (Unique registration)
I have created mu-plugins directory. located the 'cimy-user-extra-fields' directory in there and moved out cimy_user_extra_fields.php exactly like instructions say.
Then I went to Network Admin and looked for the "Network Admin -> Cimy User Extra Fields" but nothing shows. I tried all kind of variations including moving the plugin folder under the plugin directory and other solution suggested here: http://wordpress.org/support/topic/cimy-user-extra-fields-in-multisite-mode-wp-30?replies=14 and other places.
Nothing seems to be working for me. Can someone please help? This plugin does exactly what I need. The other option is to develop myself but hey... Why are there plugins for?