Register-WMIEvent works in PS5 but not PS7?

Question

The following script works in PS5_ISE & CMD.

#Just incase Event has been previously registered
Try {
  Unregister-Event -SourceIdentifier 'disk' -Force -ErrorAction Stop
}
Catch {}

$REArgs = @{Query = "Select * from __InstanceCreationEvent within 1 where targetinstance isa 'win32_logicaldisk'"
            SourceIdentifier =  "disk"
            Timeout = 1000
           }
Register-WmiEvent @REArgs

However when I attempt to run it in PS7.2.6 I get this:

PSv7>..\test\set-wmidisklistener.ps1
Register-WmiEvent: G:\BEKDocs\Scripts\test\Set-WMIDiskListener.ps1:11
Line |
  11 |  Register-WmiEvent @REArgs
     |  ~~~~~~~~~~~~~~~~~
     | The term 'Register-WmiEvent' is not recognized as a name of a cmdlet, function, script file, or executable program. Check the spelling of
     | the name, or if a path was included, verify that the path is correct and try again.

Yet...

PSv7>get-command Register*

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Function        Register-ClusteredScheduledTask                    1.0.0.0    ScheduledTasks
Function        Register-DnsClient                                 1.0.0.0    DnsClient
Function        Register-IscsiSession                              1.0.0.0    iSCSI
Function        Register-PSRepository                              2.2.5      PowerShellGet
Function        Register-PSRepository                              2.2.5      PowerShellGet
Function        Register-PSRepository                              1.0.0.1    PowerShellGet
Function        Register-ScheduledTask                             1.0.0.0    ScheduledTasks
Function        Register-StorageSubsystem                          2.0.0.0    Storage
Cmdlet          Register-ArgumentCompleter                         7.2.6.500  Microsoft.PowerShell.Core
Cmdlet          Register-CimIndicationEvent                        7.0.0.0    CimCmdlets
Cmdlet          Register-EngineEvent                               7.0.0.0    Microsoft.PowerShell.Utility
Cmdlet          Register-ObjectEvent                               7.0.0.0    Microsoft.PowerShell.Utility
Cmdlet          Register-PackageSource                             1.4.7      PackageManagement
Cmdlet          Register-PSSessionConfiguration                    7.2.6.500  Microsoft.PowerShell.Core
Cmdlet          Register-ScheduledJob                              1.1.0.0    PSScheduledJob
Cmdlet          Register-WmiEvent                                  3.1.0.0    Microsoft.PowerShell.Management
ExternalScript  RegisterManifest.ps1                                          C:\Program Files\PowerShell\7\RegisterManifest.ps1
Application     Register-CimProvider.exe                           10.0.1904… C:\Windows\system32\Register-CimProvider.exe

`Register-WmiEvent` is not part of the Microsoft.PowerShell.Management module in PS Core. — Santiago Squarzon, Aug 19 '22 at 01:44

mklement0 · Accepted Answer · 2022-08-19T02:19:51.700

The standard advice applies:

The CIM cmdlets (e.g., Get-CimInstance) superseded the WMI cmdlets (e.g., Get-WmiObject) in Windows PowerShell v3 (released in September 2012).

Therefore, the WMI cmdlets should be avoided, not least because PowerShell (Core) 7+, where all future effort will go, doesn't even have them anymore. Note that WMI still underlies the CIM cmdlets, however. For more information, see this answer.

The CIM cmdlets are contained in the CimCmdlets module. To list them all, run
Get-Command -Module CimCmdlets

While WMI still underlies the CIM cmdlets, there are differences between the Windows PowerShell-only WMI cmdlets and their CIM successors that go beyond different names, notably the need to use Invoke-CimMethod to invoke methods.

Judging simply by its name, Register-CimIndicationEvent seems to be the successor to Register-WmiEvent.

As for why you saw Register-WmiEvent in the output from get-command Register* in PowerShell (Core):

By default, you would not see this.
You would only see it if you had explicitly chosen to load the Windows PowerShell version of the Microsoft.PowerShell.Management module - which contains the WMI cmdlets - using the Windows PowerShell compatibility feature
(Import-Module -UseWindowsPowerShell Microsoft.PowerShell.Management)
- However, this is ill-advised, given the inherent limitations of this feature (also, said module contains many of PowerShell's core cmdlets, but no proxies are created for those that also exist natively in PowerShell (Core)) and the native availability of the CIM cmdlets.

Register-WMIEvent works in PS5 but not PS7?

1 Answers1