How to Fix “Permission denied (publickey)” Error with Git on Windows

Introduction

Git over SSH prevents password leaks. If your SSH key is missing or unregistered, you see:

Permission denied (publickey).
fatal: Could not read from remote repository.

This guide covers common causes and fixes on Windows.

What Is the Error?

• Occurs when the SSH client can’t find a valid key for the host.
• Git cannot authenticate you to GitHub, GitLab, Bitbucket, etc.

Common Causes

1. No SSH key generated.
2. SSH agent not running or key not added.
3. Public key not uploaded to Git host.
4. Wrong file permissions or config settings.

Solution 1: Generate a New SSH Key

1. Open Git Bash.

2. Run:

   ssh-keygen -t ed25519 -C "you@example.com"
   

3. Press Enter to accept defaults.
4. (Optionally) set a passphrase.

Solution 2: Add Your Key to the SSH Agent

In Git Bash

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

In PowerShell

1. Start the agent:

   Start-Service ssh-agent
   

2. Add the key (adjust path):

   ssh-add C:\Users\<YourUser>\.ssh\id_ed25519
   

Solution 3: Upload Your Public Key to Git Host

1. Copy your public key:

   cat ~/.ssh/id_ed25519.pub
   

2. Log in to GitHub/GitLab/Bitbucket.
3. Go to Settings → SSH and GPG keys → New SSH key.
4. Paste the key and save.

Solution 4: Verify the SSH Connection

Run in Git Bash or PowerShell:

ssh -T git@github.com

Expected response:

Hi <username>! You've successfully authenticated.

Additional Tips

• Check ~/.ssh/config:

  Host github.com
    User git
    HostName github.com
    IdentityFile ~/.ssh/id_ed25519
  

• File permissions: Ensure private key is only readable by you. In Git Bash:

  chmod 600 ~/.ssh/id_ed25519
  

• Multiple keys: Use ssh-add -l to list loaded keys.

Conclusion

Generating an SSH key, adding it to the agent, and registering it with your Git host resolves “Permission denied (publickey)” errors. Follow each step carefully on Windows.