Laravel 5 Failed opening required bootstrap/../vendor/autoload.php
Run composer with --no-scripts
composer update --no-scripts
This shall fix the issue. I tried this on Mac and Linux.
Which OS you are using ?
For Windows :
Go to Command Prompt
set path to www/{ur project}
For me : www/laravel5
Then type this command : composer install
It will automatically install all dependency in vendor/
Run composer install in your root project folder (or php composer.phar install).