Problem:
Qtranslate - Post categories are not preserved on translated posts
Solution:
1. Take a backup of the DB of your site.
2. Go to WPML -> Support -> Troubleshooting (link)
3. Once on the troubleshooting screen press the following buttons and check if it helps.
Press each button at a time and wait for the process to complete.
- 'Synchronize posts taxonomies' for your [post types].
- 'Clear the cache in WPML'
- 'Remove ghost entries from the translation tables'
- 'Fix element_type collation'
- 'Fix WPML tables collation'
- 'Set language information'
- 'Assign translation status to duplicated content'
- 'Fix terms count'
- 'Fix post type assignment for translations'
- 'Cleanup and optimize string tables'
*** Please make a backup of your database before using this.***