Laravel error in /bootstrap/start.php: \Illuminate\Foundation\Application not found

Question

So, I installed Laravel on a dev server (php5.5.3, standard installation, mcrypt installed), and I get the following error message:

Fatal error: Class \'Illumina         


        

Answer 1

Correct the composer.json. This might happen after you have added a new package configuration by dublicating the require tag.

Do not create yet another

require: {
     ..
    }

use the previous defined one.

Then follow the accepted answer to re-install the packages.