How are you checking the setting? In the .ini file or did you set up a phpinfo(); page?

If you haven't tried phpinfo(); I would check that and see what it says.

I checked it with a phpinfo-page and it says that mcrypt is enabled

Not really an answer but I'd suggest you check out Homestead. It's environment built specifically for Laravel and easy to learn. It will save you A LOT of time / hair pulling.

Are you sure it is saying it is enabled, or that PHP was built with mcrypt enabled? There is a big difference.

To enable mcrypt: $ sudo php5enmod mcrypt

Sometimes the CLI version of php will use a a different php.ini than apache. Check in the php folder and make sure that the php.ini file in that folder has it enabled.

Wamp is this way as well with two php.ini files.

Yes, it says the mcrypt is enabled.

The command sudo php5enmod crypt did not work. It says command not found.

Well, where is the php folder? I have a php.ini in the /etc/ folder. In this file I added: "extension=mcrypt.so" (http://jenssegers.be/blog/49/installing-the-php-mcrypt-extension-on-osx-10-9-mavericks)

But it still does not work :/

Try this one http://simon-davies.name/mamp/using-composer-with-mamps-version-of-php It was working to me.