coreybutler/nvm-windows · error

failed to open source file: %v

Error message

failed to open source file: %v

What it means

copyFile is the workhorse used throughout the upgrade (backup zip, .update payloads, directory tree copy) and this is its first failure mode: os.Open(src) failed. On Windows the practical causes are the file not existing (an earlier step silently failed — many WriteFile/copyFile callers ignore errors) or the file being locked exclusively by another process.

Source

Thrown at src/upgrade/upgrade.go:924

	if err != nil {
		return "", err
	}
	defer file.Close()

	var checksum string
	_, err = fmt.Fscan(file, &checksum)
	if err != nil {
		return "", err
	}

	return checksum, nil
}

func copyFile(src, dst string) error {
	// Open the source file
	sourceFile, err := os.Open(src)
	if err != nil {
		return fmt.Errorf("failed to open source file: %v", err)
	}
	defer sourceFile.Close()

	// Create the destination file
	destinationFile, err := os.Create(dst)
	if err != nil {
		return fmt.Errorf("failed to create destination file: %v", err)
	}
	defer destinationFile.Close()

	// Copy contents from the source file to the destination file
	_, err = io.Copy(destinationFile, sourceFile)
	if err != nil {
		return fmt.Errorf("failed to copy file: %v", err)
	}

	// Optionally, copy file permissions (this can be skipped if not needed)
	sourceInfo, err := os.Stat(src)

View on GitHub (pinned to 5b18223ca1)

Solutions

1. Check that the logged src path actually exists (dir listing) — a missing file usually traces back to an earlier download/extract failure.
2. Close running node/nvm/update processes and retry.
3. Run as Administrator to rule out ACLs.
4. Repair the installation manually if the tree is inconsistent (reinstall nvm-windows).

// Pre-check the source exists and is readable before copying
if fi, err := os.Stat(src); err != nil {
    return fmt.Errorf("source missing before copy: %s", src)
} else if fi.IsDir() {
    return fmt.Errorf("source is a directory, expected file: %s", src)
}

Wrap copyFile results with the src path in context; a failure here almost always traces to an earlier download/extract step — validate that step's outputs instead of retrying the copy blind.

When it happens

Trigger: Source removed between listing and copy (race with cleanup/AV); source locked by a running process (node.exe, update.exe from a previous upgrade); path constructed from an asset name containing subdirectories that were never extracted; permissions on NVM_HOME files.

Common situations: Upgrading while node processes run; antivirus quarantine deleting the source; asset paths in the manifest not matching zip contents; partially completed prior upgrade leaving the tree inconsistent.

Related errors

• failed to create destination file: %v
• error: failed to create backup directory: %v
• error: failed to create backup: %v
• error: failed to copy update.exe: %v
• failed to create destination directory %s: %v

AI-assisted analysis of coreybutler/nvm-windows@5b18223ca1 (2026-08-15). Data as JSON: /api/errors/6687fef6d8092d85. Report an issue: GitHub.