TYPO3 Core

Confirm that issue.

However, I was able to work around it by pre-installing the dependency that caused this (opened t3d file, cmd+f -> 'extensionDependencies'). So it seems to be "only" incorrect dependency-not-found handling.

The sysext "em" got replaced by "extensionmanager".
However there is at least one place in the core, which still tries to check for the extension "em".

typo3/sysext/impexp/Classes/Controller/ImportExportController.php, about line 857
TYPO3\CMS\Impexp\Controller\ImportExportController, method importData

$emURL = $this->doc->backPath . \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::extRelPath('em') . 'classes/index.php?CMD[requestInstallExtensions]=' . implode(',', $extKeysToInstall) . '&returnUrl=' . rawurlencode($thisScriptUrl);

This URL needs to be adjusted for the new new ExtensionManager.

Can confirm this bug for Typo3 6.1.7. Steps to reproduce:

1) Export Typo3/6.1.7 from server A into .t3d
2) Copy .t3d to server B.
3) Import .t3d on server B (also Typo3 6.1.7)

Result:
TYPO3 Fatal Error: Extension key "em" is NOT loaded!

Expected result:
Data should be imported.