coreybutler/nvm-windows · error

failed to copy subdirectory: %w

Error message

failed to copy subdirectory: %w

What it means

Inside copyDir()'s entry loop, a nested directory is handled by a recursive copyDir(srcPath, destPath) call. This error means the recursion into a subdirectory failed; the wrapped chain (read source directory / create destination directory / copy file / ...) names the exact nested failure. Depth of nesting does not itself cause the error, but long resulting paths can.

Source

Thrown at src/utility/rename.go:106

	entries, err := os.ReadDir(old)
	if err != nil {
		return fmt.Errorf("failed to read source directory: %w", err)
	}

	// Ensure destination directory exists
	err = os.MkdirAll(new, os.ModePerm)
	if err != nil {
		return fmt.Errorf("failed to create destination directory: %w", err)
	}

	for _, entry := range entries {
		srcPath := filepath.Join(old, entry.Name())
		destPath := filepath.Join(new, entry.Name())

		if entry.IsDir() {
			err = copyDir(srcPath, destPath)
			if err != nil {
				return fmt.Errorf("failed to copy subdirectory: %w", err)
			}
		} else {
			err = copyFile(srcPath, destPath)
			if err != nil {
				return fmt.Errorf("failed to copy file: %w", err)
			}
		}
	}

	return nil
}

View on GitHub (pinned to 5b18223ca1)

Solutions

1. Unwrap the error chain to the deepest cause and fix that specific entry (unlock file, free space, fix permissions).
2. Stop node/npm processes and retry.
3. Enable Windows long-path support for deep node_modules trees: set registry LongPathsEnabled=1.
4. Run elevated and add an antivirus exclusion for NVM_HOME.

// Pre-walk the tree to detect unreadable subdirectories before copying
filepath.WalkDir(old, func(p string, d fs.DirEntry, err error) error {
    if err != nil { return fmt.Errorf("pre-check failed at %s: %w", p, err) }
    if d.IsDir() { if _, e := os.ReadDir(p); e != nil { return e } }
    return nil
})

err := copyTree(old, new)
if err != nil && strings.Contains(err.Error(), "copy subdirectory") {
    killNodeProcesses()
    err = copyTree(old, new) // one retry after unlocking
}

When it happens

Trigger: Recursive copy of a node version tree where some nested directory (e.g. node_modules\<pkg>\bin) cannot be read, its destination cannot be created, or any file inside it is locked/read-only.

Common situations: node_modules with deeply nested or locked packages; running node processes inside the tree; path length exceeding MAX_PATH (~260 chars) with long paths disabled; antivirus interference.

Related errors

• failed to copy directory: %w
• failed to read source directory: %w
• failed to copy file: %w
• failed to open source file: %w
• failed to create destination directory: %w

AI-assisted analysis of coreybutler/nvm-windows@5b18223ca1 (2026-08-15). Data as JSON: /api/errors/b81a49cd6cab62c7. Report an issue: GitHub.