---
title: "A fatal error occurs when installing Composer dependencies with Drush"
date: "2025-04-03T06:36:22+00:00"
summary: "Troubleshoot and fix fatal errors when installing Composer dependencies with Drush. Learn how to update Composer and resolve issues."
image:
type: "article"
url: "/drupal-starter-kits/add-ons/content-hub/help/66271-fatal-error-occurs-when-installing-composer-dependencies-drush"
id: "9008e93b-8e45-446d-8d92-a807672dd909"
---

Composer Manager depends on the Composer Drush extension to install the Composer tool.

### Possible cause: Outdated Composer

If you run `drush composer-manager` commands and see errors like the following, try updating your Composer Drush extension.

    [RuntimeException]
    Could not load package...
    [UnexpectedValueException]
    Could not parse version constraint...

To resolve this issue, delete the current version of the Composer Drush extension and reinstall it by running the following commands ( `8.x` is the correct version):

    rm -Rf ~/.drush/composer
    drush dl composer-8.x

Then run the following command inside of your Drupal installation:

`drush composer-manager install`