This thread is resolved. Here is a description of the problem and solution.
Problem:Can't translate media files – "Save" button is disabled
Solution:Deactivating the plugin "Schema & Structured Data for WP & AMP", seems to resolve this issue.
This is the technical support forum for WPML - the multilingual WordPress plugin.
Everyone can read, but only WPML clients can post here. WPML team is replying on the forum 6 days per week, 22 hours per day.