Update to 5.1 breaks Get-WindowsFeature when Carbon module is installed

I’ve been testing WMF 5.1 recently and noticed a random issue. After installing WMF 5.1 I could no longer run Get-WindowsFeature. I get the following error:

PS C:> Get-WindowsFeature
Get-WindowsFeature : The term ‘Get-WindowsFeature’ is not recognized as the name of a cmdlet, function, script file,
or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and
try again.
At line:1 char:1

  • Get-WindowsFeature
  •   + CategoryInfo          : ObjectNotFound: (Get-WindowsFeature:String) [], CommandNotFoundException
      + FullyQualifiedErrorId : CommandNotFoundException

Tab complete still works for the cmdlet however. After some digging, I figured out that the issue happens because we have the Carbon module installed (PowerShell Gallery | Carbon 2.4.1) which is utilized by our DSC configuration. If I explicitly run Import-Module Servermanager, Get-WindowsFeature works fine. When I delete Carbon from the server, the Get-WindowsFeature cmdlet works without any issues.

It worked fine with WMF 5.0. It only breaks when 5.1 is installed. I did notice that Carbon has a function in its Functions folder called Get-WindowsFeature.ps1. That function is also listed in the module manifest under “FunctionsToExport”. If I remove Get-WindowsFeature from FunctionsToExport, the Get-WindowsFeature cmdlet works again.

I’m wondering why this module would work fine under WMF 5.0 but breaks now under 5.1. I can remove Get-WindowsFeature from FunctionsToExport as a temporary fix but I’d rather not rely on that long term since we don’t maintain that module. Has anyone else seen an issue like this?

You might report this on the PowerShell GitHub repo as an issue, or on the UserVoice page. But it’s very likely a naming collision on your system - if you’ve got two things exporting the same function/command name, it’s going to use the last-one-in when you try to run the command. Honestly, Carbon shouldn’t be using Get-WindowsFeature as a name - you might mention this to that author, first.