A node reference is empty, although the multilingual support is enabled, and the node is translated I just created a multilingual site (English-French) using Drupal 7 with the module Internationalization 7.x-1.4.
Everything is working fine except with the module References 7.x-2.0. For instance, I created a content type "School" so that each user is affiliated to a school (User A --> School 1, User B --> School 2, etc.), meaning I simply added a node reference to "School" in the user account settings. But here is the problem: if a user chooses a school on the English version of the site it won't remember the school choice on the French version (the node reference becomes empty) and vice versa. 

How do I solve this?

I did enable the multilingual support for "School" with translation.
Have a look at this.

http://www.ostraining.com/blog/drupal/multi-lingual-drupal/