I can't get the following code for Detecting USB Device Insertion to work on my Windows 10 (64 bit) computer with Python 3.7.

import win32serviceutil
import win32service
import win32event
import servicemanagerimport win32gui
import win32gui_struct
struct = win32gui_struct.struct
pywintypes = win32gui_struct.pywintypes
import win32conGUID_DEVINTERFACE_USB_DEVICE = "{A5DCBF10-6530-11D2-901F-00C04FB951ED}"
DBT_DEVICEARRIVAL = 0x8000
DBT_DEVICEREMOVECOMPLETE = 0x8004import ctypes#
# Cut-down clone of UnpackDEV_BROADCAST from win32gui_struct, to be
# used for monkey-patching said module with correct handling
# of the "name" param of DBT_DEVTYPE_DEVICEINTERFACE
#
def _UnpackDEV_BROADCAST (lparam):if lparam == 0: return Nonehdr_format = "iii"hdr_size = struct.calcsize (hdr_format)hdr_buf = win32gui.PyGetMemory (lparam, hdr_size)size, devtype, reserved = struct.unpack ("iii", hdr_buf)# Due to x64 alignment issues, we need to use the full format string over# the entire buffer.  ie, on x64:# calcsize('iiiP') != calcsize('iii')+calcsize('P')buf = win32gui.PyGetMemory (lparam, size)extra = {}if devtype == win32con.DBT_DEVTYP_DEVICEINTERFACE:fmt = hdr_format + "16s"_, _, _, guid_bytes = struct.unpack (fmt, buf[:struct.calcsize(fmt)])extra['classguid'] = pywintypes.IID (guid_bytes, True)extra['name'] = ctypes.wstring_at (lparam + struct.calcsize(fmt))else:raise NotImplementedError("unknown device type %d" % (devtype,))return win32gui_struct.DEV_BROADCAST_INFO(devtype, **extra)
win32gui_struct.UnpackDEV_BROADCAST = _UnpackDEV_BROADCASTclass DeviceEventService (win32serviceutil.ServiceFramework):_svc_name_ = "DevEventHandler"_svc_display_name_ = "Device Event Handler"_svc_description_ = "Handle device notification events"def __init__(self, args):win32serviceutil.ServiceFramework.__init__ (self, args)self.hWaitStop = win32event.CreateEvent (None, 0, 0, None)## Specify that we're interested in device interface# events for USB devices#filter = win32gui_struct.PackDEV_BROADCAST_DEVICEINTERFACE (GUID_DEVINTERFACE_USB_DEVICE)self.hDevNotify = win32gui.RegisterDeviceNotification (self.ssh, # copy of the service status handlefilter,win32con.DEVICE_NOTIFY_SERVICE_HANDLE)## Add to the list of controls already handled by the underlying# ServiceFramework class. We're only interested in device events#def GetAcceptedControls(self):rc = win32serviceutil.ServiceFramework.GetAcceptedControls (self)rc |= win32service.SERVICE_CONTROL_DEVICEEVENTreturn rc## Handle non-standard service events (including our device broadcasts)# by logging to the Application event log#def SvcOtherEx(self, control, event_type, data):if control == win32service.SERVICE_CONTROL_DEVICEEVENT:info = win32gui_struct.UnpackDEV_BROADCAST(data)## This is the key bit here where you'll presumably# do something other than log the event. Perhaps pulse# a named event or write to a secure pipe etc. etc.#if event_type == DBT_DEVICEARRIVAL:servicemanager.LogMsg (servicemanager.EVENTLOG_INFORMATION_TYPE,0xF000,("Device %s arrived" % info.name, ''))elif event_type == DBT_DEVICEREMOVECOMPLETE:servicemanager.LogMsg (servicemanager.EVENTLOG_INFORMATION_TYPE,0xF000,("Device %s removed" % info.name, ''))## Standard stuff for stopping and running service; nothing# specific to device notifications#def SvcStop(self):self.ReportServiceStatus (win32service.SERVICE_STOP_PENDING)win32event.SetEvent (self.hWaitStop)def SvcDoRun(self):win32event.WaitForSingleObject (self.hWaitStop, win32event.INFINITE)servicemanager.LogMsg (servicemanager.EVENTLOG_INFORMATION_TYPE,servicemanager.PYS_SERVICE_STOPPED,(self._svc_name_, ''))if __name__=='__main__':win32serviceutil.HandleCommandLine (DeviceEventService)

1. I start the script with the following command: python main.py start

2. Then the following error messages appear in the command prompt:

Starting service DevEventHandler Error starting service: Access denied

3. I then ran the script with administrator privileges: runas /user:administrator "python main.py start"

4. Another error messages appear in the command prompt:

Starting service DevEventHandler Error starting service: The specified service does not exist as an installed service.

How can the 'The specified service does not exist as an installed service' error be fixed?

I tested with Python 3.8.2 x64.

1. Install pywin32 (pip install pywin32)
2. Install the current/last version (1.5) of the WMI module from https://github.com/tjguk/wmi (pip install -e git+https://github.com/tjguk/wmi.git#egg=wmi)
3. run a script (test.py in my case), like:

import wmiraw_wql = "SELECT * FROM __InstanceCreationEvent WITHIN 2 WHERE TargetInstance ISA \'Win32_USBHub\'"
c = wmi.WMI ()
watcher = c.watch_for(raw_wql=raw_wql)
while 1:usb = watcher ()print(usb)

4. plug in a USB device. Output looks like:

(wmi-py) C:\Users\USER\Source\wmi-py>py test.pyinstance of Win32_USBHub
{Caption = "USB Composite Device";ConfigManagerErrorCode = 0;ConfigManagerUserConfig = FALSE;CreationClassName = "Win32_USBHub";Description = "USB Composite Device";
...

Many thanks to the WMI module author, and the Windows nerds' discussion here Detecting USB drive insertion and removal using windows service and c#