cloudflare/cloudflared · error

error retrieving output from command '%s': %w

Error message

error retrieving output from command '%s': %w

What it means

collectMemoryInformation on Windows runs a PowerShell command (Get-CimInstance Win32_OperatingSystem | Select FreeVirtualMemory, TotalVirtualMemorySize | Format-List) and this error wraps any command.Output() failure. It means PowerShell could not be launched, the command was cancelled, or it exited non-zero — no memory stdout was produced for parsing. The wrapped command string and error reveal the exact launch/exit cause.

Source

Thrown at diagnostic/system_collector_windows.go:107

	return info, err
}

func collectMemoryInformation(ctx context.Context) (*MemoryInformation, string, error) {
	const (
		memoryTotalPrefix     = "TotalVirtualMemorySize"
		memoryAvailablePrefix = "FreeVirtualMemory"
	)

	command := exec.CommandContext(
		ctx,
		"powershell",
		"-Command",
		"Get-CimInstance -Class Win32_OperatingSystem | Select-Object FreeVirtualMemory, TotalVirtualMemorySize | Format-List",
	)

	stdout, err := command.Output()
	if err != nil {
		return nil, "", fmt.Errorf("error retrieving output from command '%s': %w", command.String(), err)
	}

	output := string(stdout)

	// the result of the command above will return values in bytes hence
	// they need to be converted to kilobytes
	mapper := func(field string) (uint64, error) {
		value, err := strconv.ParseUint(field, 10, 64)
		return uint64(float64(value) * kiloBytesScale), err
	}

	memoryInfo, err := ParseMemoryInformationFromKV(output, memoryTotalPrefix, memoryAvailablePrefix, mapper)
	if err != nil {
		return nil, output, err
	}

	// returning raw output in case other collected information
	// resulted in errors

View on GitHub (pinned to 2253eeeb25)

Solutions

1. Check the wrapped error: 'executable file not found' means restore Windows PowerShell (optional features) or patch the environment so powershell.exe is on PATH.
2. Ensure the WMI/Winmgmt service is running: 'Get-Service winmgmt' and 'winmgmt /verifyrepository' — restart or repair the repository if broken.
3. Run the exact Get-CimInstance command manually in PowerShell to see any non-zero exit cause (CIM errors surface there).
4. If AppLocker/WDAC blocks powershell.exe, add an allow rule for the cloudflared process or script path.
5. If the error is context deadline exceeded, investigate slow CIM/WMI startup and increase the diagnostic timeout.

Example fix

// before: only PowerShell 7 present
C:\> where powershell  →  not found

// after: restore Windows PowerShell optional feature
Add-WindowsCapability -Online -Name Microsoft.Windows.PowerShell.ISE~~~~0.0.1.0
# or ensure C:\Windows\System32\WindowsPowerShell\v1.0 is on PATH

if _, err := exec.LookPath("powershell"); err != nil {
    return fmt.Errorf("Windows PowerShell not on PATH: %w", err)
}
if svc, err := exec.Command("sc", "query", "winmgmt").Output(); err != nil || !strings.Contains(string(svc), "RUNNING") {
    return fmt.Errorf("WMI service (winmgmt) not running")
}

func powershellReady() bool {
    if _, err := exec.LookPath("powershell"); err != nil {
        return false
    }
    out, err := exec.Command("powershell", "-NoProfile", "-Command", "Get-Service winmgmt").Output()
    return err == nil && strings.Contains(string(out), "Running")
}

info, raw, err := collector.Collect(ctx)
if err != nil && strings.Contains(err.Error(), "error retrieving output from command 'powershell") {
    log.Warn().Err(err).Msg("Windows memory collection failed; check PowerShell and WMI health")
    // retry once after restarting winmgmt, or skip the memory section
}

When it happens

Trigger: Collect() calls collectMemoryInformation on Windows; 'powershell' is not on PATH (PowerShell removed or only pwsh installed), the Win32_OperatingSystem CIM query fails (WMI/CIM service stopped), the context deadline expires, or a security policy blocks powershell.exe.

Common situations: Systems where Windows PowerShell was uninstalled and only PowerShell 7 (pwsh.exe) exists, the WMI (Winmgmt) service disabled or broken in stripped-down Windows images, endpoint security (AppLocker/WDAC) blocking powershell.exe, or slow CIM queries exceeding the diagnostic timeout.

Related errors

• error opening file %s:%w
• couldn't parse index from timeout hop: %w
• parsing os information: %w, key=%s
• parsing memory information: %w, key=%s
• error retrieving output from command '%s': %w

AI-assisted analysis of cloudflare/cloudflared@2253eeeb25 (2026-09-06). Data as JSON: /api/errors/474e77dbec8cabae. Report an issue: GitHub.