What causes "cannot install new nomad binary - %s" in hashicorp/nomad?

Ensure the temp directory and the install path are on the same volume (set TMP accordingly)

cannot install new nomad binary - %s

Error message

cannot install new nomad binary - %s

What it means

binaryInstall wraps the error from os.Rename(dstFile.Name(), opts.binaryPath), which moves the staged temp copy to the final install path. On Windows, rename across devices or onto a locked target fails, so the new binary could not be installed. The wrapped error explains why.

Source

Thrown at command/windows_service_install.go:361

	dstFile, err := os.CreateTemp(os.TempDir(), "nomad*")
	if err != nil {
		return fmt.Errorf("cannot create copy - %s", err)
	}
	defer dstFile.Close()

	if _, err = io.Copy(dstFile, exeFile); err != nil {
		return fmt.Errorf("cannot write nomad binary for install - %s", err)
	}
	dstFile.Close()

	// With a copy ready to be moved into place, ensure that
	// the path is clear then move the file.
	if err = os.RemoveAll(opts.binaryPath); err != nil {
		return fmt.Errorf("cannot remove existing nomad binary install - %s", err)
	}

	if err = os.Rename(dstFile.Name(), opts.binaryPath); err != nil {
		return fmt.Errorf("cannot install new nomad binary - %s", err)
	}

	return nil
}

View on GitHub (pinned to 482b49bf1a)

Solutions

Ensure the temp directory and the install path are on the same volume (set TMP accordingly)
Stop the running nomad service so the target path is not locked
Run elevated so the rename is permitted
Remove any residual file at the target path manually, then retry the install

Example fix

// before: TMP on D: while binaryPath on C:
set TMP=D:\tmp
// after: same volume as install target
set TMP=C:\Windows\Temp

Defensive patterns

Strategy: validation

Validate before calling

td := os.TempDir()
if filepath.VolumeName(td) != filepath.VolumeName(binaryPath) {
    return fmt.Errorf("temp dir %s and install path %s on different volumes", td, binaryPath)
}

Try / catch

if err := installCmd.Run(); err != nil {
    if strings.Contains(err.Error(), "cannot install new nomad binary") {
        // align TMP volume with install path, unlock target, retry
    }
}

Prevention

Keep TMP on the same volume as the install directory
Clear any residual file at the target path before install
Stop the running service so the target is not locked

When it happens

Trigger: os.Rename fails when the temp dir and binaryPath are on different volumes (rename is not cross-device on Windows), the target path still exists/is locked, or permissions deny the move during binaryInstall.

Common situations: TMP on a different drive than the install directory; leftover target file that RemoveAll missed; target locked by the still-running service.

Related errors

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/10f5524a4709b75b. Report an issue: GitHub.