hashicorp/nomad · error

cannot create data directory

Error message

cannot create data directory - %s

What it means

configInstall creates both config and data directories; this error wraps failure of winPaths.CreateDirectory(opts.dataDir, true) for the data directory. Nomad cannot provision its state directory, so installation aborts before writing the default config.

Solutions

1. Run the installer from an elevated (Administrator) shell
2. Pick a writable -data-dir such as C:\ProgramData\nomad\data
3. Check for a conflicting file at the data-dir path and remove it
4. Verify free disk space and that the volume is writable

Example fix

// before
nomad windows service install -data-dir "C:\nomad\data" // parent not writable
// after
nomad windows service install -data-dir "C:\ProgramData\nomad\data"

// Pre-check the data dir location before install
if fi, err := os.Stat(dataDir); err == nil && !fi.IsDir() {
    return fmt.Errorf("%s exists and is not a directory", dataDir)
}
probe := filepath.Join(filepath.Dir(dataDir), ".nomad_write_probe")
if err := os.WriteFile(probe, nil, 0o600); err != nil {
    return fmt.Errorf("data-dir parent not writable: %w", err)
}
os.Remove(probe)

When it happens

Trigger: Running 'nomad windows service install' when the expanded dataDir cannot be created: insufficient privileges, an existing file blocking the directory path, invalid characters, or unavailable disk/drive.

Common situations: Custom -data-dir under a protected path without elevation; a file named 'data' already exists in the config root; disk full or read-only volume; path exceeding Windows MAX_PATH limits.

Related errors

• cannot create configuration directory
• cannot create copy
• cannot generate data path
• cannot open current nomad path for install
• could not create binary install directory

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/8bff7c1cd4b631f6. Report an issue: GitHub.

Appendix: source

Thrown at command/windows_service_install.go:270

	if opts.dataDir == "" {
		opts.dataDir = filepath.Join(winsvc.WINDOWS_INSTALL_APPDATA_DIRECTORY, "data")
	}

	var err error
	if opts.configDir, err = c.winPaths.Expand(opts.configDir); err != nil {
		return fmt.Errorf("cannot generate configuration path - %s", err)
	}
	if opts.dataDir, err = c.winPaths.Expand(opts.dataDir); err != nil {
		return fmt.Errorf("cannot generate data path - %s", err)
	}

	// Ensure directories exist
	if err = c.winPaths.CreateDirectory(opts.configDir, true); err != nil {
		return fmt.Errorf("cannot create configuration directory - %s", err)
	}

	if err = c.winPaths.CreateDirectory(opts.dataDir, true); err != nil {
		return fmt.Errorf("cannot create data directory - %s", err)
	}

	// Check if any configuration files exist
	matches, _ := filepath.Glob(filepath.Join(opts.configDir, "*"))
	if len(matches) < 1 {
		f, err := os.Create(filepath.Join(opts.configDir, "config.hcl"))
		if err != nil {
			return fmt.Errorf("could not create default configuration file - %s", err)
		}
		fmt.Fprintf(f, strings.TrimSpace(`
# Full configuration options can be found at https://developer.hashicorp.com/nomad/docs/configuration

data_dir  = "%s"
bind_addr = "0.0.0.0"

server {
  # license_path is required for Nomad Enterprise as of Nomad v1.1.1+
  #license_path = "%s\license.hclic"

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