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wmi Tutorial

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WMI - Windows Management Instrumentation

What is it?

Windows Management Instrumentation (WMI) is Microsoft’s implementation of Web-Based Enterprise Management (WBEM), an industry initiative to provide a Common Information Model (CIM) for pretty much any information about a computer system.

The Python WMI module is a lightweight wrapper on top of the pywin32 extensions, and hides some of the messy plumbing needed to get Python to talk to the WMI API. It’s pure Python and has been tested against all versions of Python from 2.4 to 3.2. It should work with any recent version of pywin32.

How do I install it?

When all’s said and done, it’s just a module. But for those who like setup programs:

python install

Or download the Windows installer and double-click.

How do I use it?

Have a look at the wmi Tutorial or the wmi Cookbook. As a quick taster, try this, to find all Automatic services which are not running and offer the option to restart each one:

import wmi

c = wmi.WMI ()
for s in c.Win32_Service (StartMode="Auto", State="Stopped"):
  if raw_input ("Restart %s? " % s.Caption).upper () == "Y":
    s.StartService ()

What’s Changed?

See the Changes document


If you’re running a recent Python (2.4+) on a recent Windows (2k, 2k3, XP) and you have Mark Hammond’s win32 extensions installed, you’re probably up-and-running already. Otherwise...


If you’re running Win9x / NT4 you’ll need to get WMI support from Microsoft. Microsoft URLs change quite often, so I suggest you do this:

Python (just in case you didn’t know)

pywin32 (was win32all)

Specifically, builds 154/155 fixed a problem which affected the WMI moniker construction. You can still work without this fix, but some more complex monikers will fail. (The current build is 214 so you’re probably ok unless you have some very stringent backwards-compatible requirement).


(NB my own experience over several systems is that this step isn’t necessary. However, if you have problems...) You may have to compile makepy support for some typelibs. The following are reported to be significant:

  • Microsoft WMI Scripting Library
  • WMI ADSI Extension Type Library
  • WMICntl Type Library

If you’ve not done this before, start the PythonWin environment, select Tools > Com Makepy utility from the menu, select the library by name, and click [OK].