Fatal error: Uncaught Error: Class 'Magento\Framework\Autoload\AutoloaderRegistry' not found

[DLSoftwares]

Hello, 

I am getting below error when I'm accessing my magento2 from browser. Actually i downloaded the 2.2.0 version of magento2 from mage site and I saw in downloaded magento2 directory all the files are present in vendor directory and I want to install magento2 as like fresh one but when I accessing the magento2 directory from address and magento2 directory I got this error. Please Help How to install magento2.....?

Fatal error: Uncaught Error: Class mage\framework\auto-load\auto-loader-registry not found

[Manthan Dave]

You need to run composer install  command first from your magento2 root directory in your SSH terminal.

Then  do setup !! it will works

[DLSoftwares]

Thanks for reply I did it and I got following message :

Do not run Composer as root/super user! See https://getcomposer.org/root for details
Loading composer repositories with package information
Installing dependencies (including require-Dev) from lock file
Nothing to install or update
Generating auto-load files

[Manthan Dave]

create one composer.json file in root directory or if its there then check its content !!

composer.json file code :

{
    "name": "magento/project-community-edition",
    "description": "eCommerce Platform for Growth (Community Edition)",
    "type": "project",
    "version": "2.2.0",
    "license": [
        "OSL-3.0",
        "AFL-3.0"
    ],
    "require": {
        "magento/product-community-edition": "2.2.0",
        "composer/composer": "@alpha",
        "magento/module-bundle-sample-data": "100.2.*",
        "magento/module-catalog-sample-data": "100.2.*",
        "magento/module-customer-sample-data": "100.2.*",
        "magento/module-theme-sample-data": "100.2.*",
        "magento/module-widget-sample-data": "100.2.*",
        "magento/module-cms-sample-data": "100.2.*",
        "magento/module-review-sample-data": "100.2.*",
        "magento/module-tax-sample-data": "100.2.*",
        "magento/module-msrp-sample-data": "100.2.*",
        "magento/module-sales-sample-data": "100.2.*",
        "magento/module-catalog-rule-sample-data": "100.2.*",
        "magento/module-configurable-sample-data": "100.2.*",
        "magento/module-product-links-sample-data": "100.2.*",
        "magento/module-wishlist-sample-data": "100.2.*",
        "magento/module-sales-rule-sample-data": "100.2.*",
        "magento/module-downloadable-sample-data": "100.2.*",
        "magento/module-grouped-product-sample-data": "100.2.*",
        "magento/module-swatches-sample-data": "100.2.*",
        "magento/sample-data-media": "100.2.*",
        "magento/module-offline-shipping-sample-data": "100.2.*"
    },
    "require-dev": {
        "phpunit/phpunit": "~6.2.0",
        "squizlabs/php_codesniffer": "3.0.1",
        "phpmd/phpmd": "@stable",
        "pdepend/pdepend": "2.5.0",
        "friendsofphp/php-cs-fixer": "~2.1.1",
        "lusitanian/oauth": "~0.8.10",
        "sebastian/phpcpd": "2.0.4"
    },
    "autoload": {
        "psr-4": {
            "Magento\\Framework\\": "lib/internal/Magento/Framework/",
            "Magento\\Setup\\": "setup/src/Magento/Setup/",
            "Magento\\": "app/code/Magento/"
        },
        "psr-0": {
            "": [
                "app/code/"
            ]
        },
        "files": [
            "app/etc/NonComposerComponentRegistration.php"
        ],
        "exclude-from-classmap": [
            "**/dev/**",
            "**/update/**",
            "**/Test/**"
        ]
    },
    "autoload-dev": {
        "psr-4": {
            "Magento\\Sniffs\\": "dev/tests/static/framework/Magento/Sniffs/",
            "Magento\\Tools\\": "dev/tools/Magento/Tools/",
            "Magento\\Tools\\Sanity\\": "dev/build/publication/sanity/Magento/Tools/Sanity/",
            "Magento\\TestFramework\\Inspection\\": "dev/tests/static/framework/Magento/TestFramework/Inspection/",
            "Magento\\TestFramework\\Utility\\": "dev/tests/static/framework/Magento/TestFramework/Utility/"
        }
    },
    "minimum-stability": "stable",
    "repositories": [
        {
            "type": "composer",
            "url": "https://repo.magento.com/"
        }
    ],
    "extra": {
        "magento-force": "override"
    }
}

then run composer install command

then run composer update command

then try to setup your magento2

[DLSoftwares]

yes, I checked the file and it's contents all are present in root directory 

[Manthan Dave]

run composer update command !!

then try to installed magento2 , it will works !!! 

[DLSoftwares]

Yes, as you said I ran composer update command it updated 45 packages only and still on web page it showing that error.

See :

ubuntu@ip-172-21-176-65:/opt/lampp/htdocs/DLMART$ sudo php ~/composer_setup/composer update
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 0 installs, 45 updates, 0 removals
- Updating magento/magento-composer-installer (0.1.12 => 0.1.13): Loading from cache
- Updating phpseclib/phpseclib (2.0.6 => 2.0.10): Loading from cache
- Updating symfony/polyfill-mbstring (v1.5.0 => v1.7.0): Loading from cache
- Updating symfony/console (v2.8.27 => v2.8.36): Loading from cache
- Updating symfony/event-dispatcher (v2.8.27 => v2.8.36): Loading from cache
- Updating symfony/process (v2.8.27 => v2.8.36): Loading from cache
- Updating zendframework/zend-eventmanager (2.6.3 => 2.6.4): Loading from cache
- Updating zendframework/zend-code (3.1.0 => 3.3.0): Loading from cache
- Updating zendframework/zend-console (2.6.0 => 2.7.0): Loading from cache
- Updating zendframework/zend-db (2.8.2 => 2.9.2): Loading from cache
- Updating zendframework/zend-validator (2.10.1 => 2.10.2): Loading from cache
- Updating zendframework/zend-servicemanager (2.7.8 => 2.7.10): Loading from cache
- Updating zendframework/zend-inputfilter (2.7.4 => 2.8.1): Loading from cache
- Updating zendframework/zend-form (2.10.2 => 2.11.0): Loading from cache
- Updating zendframework/zend-http (2.6.0 => 2.7.0): Loading from cache
- Updating zendframework/zend-modulemanager (2.8.0 => 2.8.2): Loading from cache
- Updating zendframework/zend-serializer (2.8.0 => 2.8.1): Loading from cache
- Updating zendframework/zend-session (2.8.0 => 2.8.5): Loading from cache
- Updating zendframework/zend-soap (2.6.0 => 2.7.0): Loading from cache
- Updating zendframework/zend-view (2.9.0 => 2.10.0): Loading from cache
- Updating symfony/finder (v3.3.9 => v3.4.6): Loading from cache
- Updating symfony/filesystem (v3.3.9 => v3.4.6): Loading from cache
- Updating seld/jsonlint (1.6.1 => 1.7.1): Loading from cache
- Updating justinrainbow/json-schema (5.2.1 => 5.2.7): Loading from cache
- Updating composer/spdx-licenses (1.1.6 => 1.3.0): Loading from cache
- Updating composer/ca-bundle (1.0.8 => 1.1.0): Loading from cache
- Updating magento/module-sales-sample-data (100.2.0 => 100.2.1): Downloading (100%)
- Updating symfony/polyfill-php54 (v1.5.0 => v1.7.0): Loading from cache
- Updating symfony/polyfill-php55 (v1.5.0 => v1.7.0): Loading from cache
- Updating paragonie/random_compat (v2.0.10 => v2.0.11): Loading from cache
- Updating symfony/polyfill-php70 (v1.5.0 => v1.7.0): Loading from cache
- Updating symfony/polyfill-php72 (v1.5.0 => v1.7.0): Loading from cache
- Updating symfony/stopwatch (v3.3.9 => v3.4.6): Loading from cache
- Updating symfony/config (v3.3.9 => v3.4.6): Loading from cache
- Updating symfony/dependency-injection (v3.3.9 => v3.4.6): Loading from cache
- Updating myclabs/deep-copy (1.6.1 => 1.7.0): Loading from cache
- Updating doctrine/instantiator (1.0.5 => 1.1.0): Loading from cache
- Updating webmozart/assert (1.2.0 => 1.3.0): Loading from cache
- Updating phpdocumentor/reflection-docblock (4.1.1 => 4.3.0): Loading from cache
- Updating phpspec/prophecy (v1.7.2 => 1.7.5): Loading from cache
- Updating phpunit/php-token-stream (2.0.1 => 2.0.2): Loading from cache
- Updating phpunit/php-file-iterator (1.4.2 => 1.4.5): Loading from cache
- Updating phpunit/php-code-coverage (5.2.2 => 5.3.0): Loading from cache
- Updating sebastian/finder-facade (1.2.1 => 1.2.2): Loading from cache
Package sjparkinson/static-review is abandoned, you should avoid using it. Use phpro/grumphp instead.
Writing lock file
Generating autoload files

Output On Browser :

[Manthan Dave]

Its a different issue from installation.

For that you need to remove it first and then need to run setup:upgrade command !!

better to follow this link for this issue - https://community.magento.com/t5/Hosting-Performance/Package-sjparkinson-static-review-is-abandoned/...