How to Fix Emacs Package Installation Errors — ELPA and MELPA Setup

In this tutorial, you'll learn about How to Fix Emacs Package Installation Errors. We cover key concepts, practical examples, and best practices.

The Problem

Emacs fails to install a package:

Failed to download 'melpa' archive.

or:

Package `company-0.9.13' is unavailable

Quick Fix

Step 1: Configure package archives

WRONG — only GNU ELPA:

(require 'package)
(package-initialize)

RIGHT — add MELPA:

(require 'package)
(add-to-list 'package-archives
             '("melpa" . "https://melpa.org/packages/") t)
(package-initialize)

Step 2: Refresh package list

M-x package-refresh-contents

Or in init.el:

(unless package-archive-contents
  (package-refresh-contents))

Step 3: Fix GPG key errors

gpg --homedir ~/.emacs.d/elpa/gnupg \
  --keyserver keyserver.ubuntu.com \
  --recv-keys 066DAFCB81E42C40

Or disable GPG checking (not recommended):

(setq package-check-signature nil)

Step 4: Install packages programmatically

(unless (package-installed-p 'company)
  (package-install 'company))

Step 5: Use use-package

(use-package company
  :ensure t
  :config
  (global-company-mode))

Step 6: Fix dependency issues

M-x package-list-packages

Press I to mark dependencies, X to execute.

Prevention

• Add MELPA to access more packages.
• Use use-package with :ensure t.
• Import the GNU ELPA GPG key to avoid signature warnings.

Common Mistakes with package install

1. Using foldl instead of foldl' causing stack overflow on large lists
2. Forgetting deriving (Show, Eq) on custom data types needed for debugging
3. Placing the wildcard pattern first in case expressions, making all subsequent patterns unreachable

These mistakes appear frequently in real-world EMACS code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ