I've been implementing a new theme in Magento. When I wasn't seeing the changes show up, I followed advice to clear out /pub/static/ and use /bin/magento setup:static-content:deploy to rebuild the static content.
After doing so, I've lost the CSS the JS in the admin panel. Checking the path for the CSS and JS files, I'm seeing; /pub/static/adminhtml/Magento/backend/en_GB/ however Magento has only created a folder for en_US. How do I get it to create static content for the correct locale/s?
I have gone through the same problem. I have done same as you delete pub/static content but after re-deploying I didn't get the solutions. Again I installed fresh Magento. After some time again I face this issue but this time, I used the best approach. Hope this will work for you :
Use the following command from your magento root directory
sudo rm -rf var/di/* var/generation/* var/cache/* var/page_cache/* var/view_preprocessed/* var/composer_home/cache/*
sudo chmod 777 var -R
sudo chmod 777 pub -R
sudo php bin/magento setup:static-content:deploy
Repeat step 2 & 3.