Update-Module - Module PowershellGet was not installed by using Install-Module, so it cannot be updated.

Well there we go again, something that should be easy and take 5 minutes turns in to a 3 hour job.

How we got here?

Install-Module : A parameter cannot be found that matches parameter name ‘AllowPrerelease’

Okay, so if that doesn't work, then try to update it.

No bueno, this is because PowerShellGet comes builtin with Windows 2016 but it's on older version. If you want all bells and whistles you need to install newest version from PowerShellGallery.

That doesn't really help.

But what does help is going full mental.

PowerShellGet 1.0.0.1 does not update properly.

Now try the aggressive way of  forcing your will onto this module.

Browse to C:\Program Files\WindowsPowerShell\Modules\
Open the folder C:\Program Files\WindowsPowerShell\Modules\PowershellGet and delete the subfolder 1.0.0.1
Open the folder C:\Program Files\WindowsPowerShell\Modules\PackageManagement and delete the subfolder 1.0.0.1
Browse to C:\Program Files (x86)\WindowsPowerShell\Modules\
Open the folder C:\Program Files (x86)\WindowsPowerShell\Modules\PowershellGet and delete the subfolder 1.0.0.1
Open the folder C:\Program Files (x86)\WindowsPowerShell\Modules\PackageManagement and delete the subfolder 1.0.0.1

Now run Install-Module PowerShellGet -Force and Update-Module PowerShellGet

Check for correct installation and mudule version with Get-Command Install-Module.