If you receive an error that just says “The website encountered an unexpected error. Please try again later.” this could be a PHP error. To troubleshoot this error:
- Visit Acquia Dev Desktop's preferences, then click the Logs tab. That will show the file location of the Apache error logs, which will have information on PHP errors as well.
- If the logs do not show anything obvious, go back to the Dev Desktop settings, visit the Config tab, and then choose "Apache module (mod_php)" under PHP mode. That will write more descriptive error messages than the alternative.
- Refresh the site, and then check the logs again.
Some common issues related to that error message:
If the error looks something like this:
Drupal\\Core\\Database\\DatabaseAccessDeniedException: SQLSTATE  Access denied for user 'username'@'localhost' (using password: YES)
Then check to see if the settings.php file, put the <DDSETTINGS> block at the very end of the file. That will overwrite whatever custom settings you might have for a local installation with the correct settings for Dev Desktop.
If the error is a "missing plugin" error, try clearing the Drupal cache using Drush.