TYPO3 Core

The update wizards converts localconf.php to LocalConfiguration.php

Within this process, LocalConfiguration.php should be freshly created:

typo3/sysext/install/Classes/CoreUpdates/LocalConfigurationUpdate.php:
// Write out new LocalConfiguration file
\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance('TYPO3\\CMS\\Core\\Configuration\\ConfigurationManager')->writeLocalConfiguration($TYPO3_CONF_VARS);

writeLocalConfiguration() checks if the file exists with @is_file() and throws an exception if not ... so at this point, the ugrade wizard always throws exception #1346323822

One solution is to think about the file existance check in writeLocalConfiguration(), another one is to 'touch' an empty LocalConfiguration file in the wizard first. Furthermore the should show a better meaningful message if it fails (eg. the exceptions getMessage).