I followed all the steps to do the upgrade from 5.7a to 6 and I’m getting this error.
An unhandled exception has been thrown:
Doctrine\DBAL\Exception: Failed to connect to the database: An exception occurred in the driver: SQLSTATE[HY000] [14] unable to open database file in /usr/local/lib/owncloud/lib/private/DB/Connection.php:85