While attempting to write back migrated user config to %s, a

Error message

While attempting to write back migrated user config to %s, an error occurred: %s

What it means

Raised in pkg/config/app_config.go:268 during automatic user config migration. lazygit detected that the config file needs a schema migration, computed the migrated YAML content, but os.WriteFile to the config path failed (permissions, missing parent dir, read-only filesystem). The error includes the path and the underlying write error; in GUI mode the pending changes text is appended so the user can apply it manually.

Source

Thrown at pkg/config/app_config.go:268

		return content, nil
	}

	changesText := "The following changes were made:\n\n"
	changesText += strings.Join(lo.Map(changes.ToSliceFromOldest(), func(change string, _ int) string {
		return fmt.Sprintf("- %s\n", change)
	}), "")

	// Write config back
	if !isGuiInitialized {
		fmt.Printf("The user config file %s must be migrated. Attempting to do this automatically.\n", path)
		fmt.Println(changesText)
	}
	if err := os.WriteFile(path, changedContent, 0o644); err != nil {
		errorMsg := fmt.Sprintf("While attempting to write back migrated user config to %s, an error occurred: %s", path, err)
		if isGuiInitialized {
			errorMsg += "\n\n" + changesText
		}
		return nil, errors.New(errorMsg)
	}
	if !isGuiInitialized {
		fmt.Printf("Config file saved successfully to %s\n", path)
	}
	return changedContent, nil
}

// A pure function helper for testing purposes
func computeMigratedConfig(path string, content []byte, changes *ChangesSet) ([]byte, bool, error) {
	var err error
	var rootNode yaml.Node
	err = yaml.Unmarshal(content, &rootNode)
	if err != nil {
		return nil, false, fmt.Errorf("failed to parse YAML: %w", err)
	}
	var originalCopy yaml.Node
	err = yaml.Unmarshal(content, &originalCopy)
	if err != nil {

View on GitHub (pinned to c477a2959b)

Solutions

Fix ownership/permissions: 'chown -R $USER ~/.config/lazygit' and ensure write access (chmod u+w)
Free disk space or remount the config location read-write
Re-run lazygit from a terminal (isGuiInitialized=false) so the changes text prints to stdout, and apply the migration by hand
Back up then delete the stale config so lazygit regenerates defaults, then reapply custom settings

Example fix

# shell fix, not a code fix
sudo chown -R $(whoami) ~/.config/lazygit
chmod u+w ~/.config/lazygit/config.yml

Defensive patterns

Strategy: validation

Validate before calling

// Pre-flight check before launching lazygit across an upgrade:
func configWritable(path string) error {
    info, err := os.Stat(filepath.Dir(path))
    if err != nil {
        return err
    }
    if info.Mode().Perm()&0o200 == 0 {
        return fmt.Errorf("config dir %s is not writable", filepath.Dir(path))
    }
    return nil
}

Try / catch

if _, err := loadConfig(); err != nil && strings.Contains(err.Error(), "write back migrated user config") {
    // apply printed changesText manually after fixing permissions
    fmt.Println(err)
}

Prevention

Never run lazygit under sudo; fix ownership with chown if you did
Keep the config dir writable and backed up before upgrades
Run lazygit in a terminal when migrating so changesText prints for manual recovery

When it happens

Trigger: os.WriteFile(path, changedContent, 0o644) failing: config dir owned by another user, config on a read-only mount, disk full, SELinux/AppArmor denial, or the file being immutable.

Common situations: Running lazygit with sudo previously so ~/.config/lazygit is root-owned; corporate machines with enforced read-only home subpaths; config synced via a tool that locks the file; upgrading lazygit across a version that introduced a config migration.

Related errors

AI-assisted analysis of jesseduffield/lazygit@c477a2959b (2026-08-15). Data as JSON: /api/errors/4ff05d32c54228da. Report an issue: GitHub.