If you update language packs through the TYPO3 extension manager, it can happen that it will mark the update as “failed”, but if you check for updates again, it tells you there are no updates available.

Generally it behaves kind of weird with language pack updates. What’s going on and how do I fix it?

The cause of the problem is broken ZIP support in TYPO3. At least that’s what my research concluded.

To fix this, you need to set the path to the unzip utility in the TYPO3 configuration (so it doesn’t use the internal ZIP support). To do so you need to set this configuration variable:

$TYPO3_CONF_VARS['BE']['unzip_path'] = '/usr/bin/unzip';

Set it to wherever your unzip utility is located.

So what if you’re on Windows and don’t have unzip? I have no idea. Would be glad if someone told me.