Getting "Can't find the drive. The drive called 'IIS' does not exist."

The drive is provided by the WebAdministration module, so you need to install/import that module first.

How you install the module depends on your actual system and whether you use GUI or PowerShell. On a Windows Server 2008 R2 for instance you'd install the module with the following PowerShell commands:

Import-Module ServerManagerAdd-WindowsFeature Web-Scripting-Tools

After the module is installed you can load it in your script like this:

Import-Module WebAdministration

To resolve running the script (or powershell shell/exe) in Admin mode.

For those on windows server 2016 and 2019 I found that it was the Server Feature

IIS Management Console aka Web-Mgmt-Console

that needed to be turned on. If you are in an active powershell session and have import the WebAdministration module and the command

Get-PSDrive 

does not return IIS in the list. Run the following

Remove-Module WebAdministrationImport-Module WebAdministrationGet-PSDrive

Then you should see the powershell IIS drive. I suspect my issue had to do with running scripts that imported WebAdministration but were attaching the PSDrive IIS in my powershell session. Attempts to import WebAdministration again would not attaching the PSDrive to my session unless I removed it first.