Gettting errors after install drupal-8.2.6.nl.po I add Language Dutch and import drupal-8.2.6.nl.po

This error is showed on every page: sourcetext 'The file could not be created'



What should I do?
1. Uninstall dutch language?
2. reinstall dutch language?
3. change language settings?
(copying from my comment)

Sounds like your public file system is not writable, which is necessary to generate translation files for JS. When you get an error like this, always check the status report page.