Fatal error: Class 'Illuminate\Foundation\Application' not found

In my situation, I didn't have the full vendor dependencies in place (composer file was messed up during original install) - so running any artisan commands caused a failure.

I was able to use the --no-scripts flag to prevent artisan from executing before it was included. Once my dependencies were in place, everything worked as expected.

composer update --no-scripts

Just in case I trip over this error in 2 weeks again... My case: Checkout an existing project via git and pull in all dependencies via composer. Came down to the same error listed within the title of this post.

Solution:

composer dump-autoload
composer install --no-scripts

make sure everything works now as expected (no errors!)

composer update

Something is clearly corrupt in your Laravel setup and it is very hard to track without more info about your environment. Usually these 2 commands help you resolve such issues

php artisan clear-compiled
composer dump-autoload

If nothing else helps then I recommend you to install fresh Laravel 5 app and copy your application logic over, it should take around 15 min or so.

In my case composer was not installed in that directory. So I run

composer install

then error resolved. or you can try

composer update --no-scripts
cd bootstrap/cache/->rm -rf *.php
composer dump-autoload

I just fixed this problem (Different Case with same error), The answer above I tried may not work because My case were different but produced the same error. I think my vendor libraries were jumbled, I get this error by: 1. Pull from remote git, master branch is codeigniter then I do composer update on master branch, I wanted to work on laravel branch then I checkout and do composer update so I get the error,

Fatal error: Class 'Illuminate\Foundation\Application' not found in C:\cms\bootstrap\app.php on line 14

Solution: I delete the project on local and do a clone again, after that I checkout to my laravel file work's branch and do composer update then it is fixed.

I had accidentally commented out:

require __DIR__.'/../bootstrap/autoload.php';

in /public/index.php

When pasting in some debugging statements.

Easy as this, that worked for my project

Delete /vendor folder

and execute composer install

then run project php artisan serve

For latest laravel version also check your version because I was also facing this error but after update latest php version, I got rid from this error.

I can't imagine that anyone else reading this is a stupid as I was but just in case... I had accidentally removed "laravel/framework": "^5.6" from my composer.json when resolving merge conflicts.

please test below solution:

first open command prompt cmd ==> window+r and go to the location where laravel installed.

try composer require laravel/laravel

i was having same problem with this error. It turn out my Kenel.php is having a wrong syntax when i try to comply with wrong php8 syntax

The line should be

protected $commands = [
    //
];

instead of

protected array $commands = [
        //
];

run composer require laravel/framework after composer install then php artisan key:generate its work for me in kali linux

@kalhan-toress 's comment is what ACTUALLY WORKED FOR ME
remove /bootstrap/start.php,composer.lock, and the vendor and run composer install

In my case, the error was caused on initial deployment because I didn't have a .env file in that directory (because those don't belong on Github where the files were transferred from).