I have a configuration that uses a "master" core joomla, a USER master for shared users, and slaves off the user master.

In the JMS slave1 for the user master I cannot change the administration backend language. It's installed, I set my profile to use it, but it remains in another language.

I have tried to install other languages on the MASTER (for example EN-US) but they will not run on the backend administrator panel.

I have use of the EN-UK admin in all my child slaves running off the USER profile Slave.

Any thoughts?

Thanks, in advance.

Do you have forced the language in JMS with the "set default language" ?