Fixed : Sitecore 9.1 Installation Error - No registration found for extension 'OutNull' of type 'Task'

I was installing Sitecore 9.1 and started to receive error "No registration found for extension 'OutNull' of type 'Task'".

PS>TerminatingError(): "No registration found for extension 'OutNull' of type 'Task'."
>> TerminatingError(MapTasks): "The running command stopped because the preference variable "ErrorActionPreference" or common parameter is set to Stop: No registration found for extension 'OutNull' of type 'Task'."
>> TerminatingError(MapTasks): "The running command stopped because the preference variable "ErrorActionPreference" or common parameter is set to Stop: No registration found for extension 'OutNull' of type 'Task'."
Install-SitecoreConfiguration : No registration found for extension 'OutNull' of type 'Task'.
At C:\resourcefiles91\XP0-SingleDeveloper.ps1:74 char:1
+ Install-SitecoreConfiguration @singleDeveloperParams *>&1 | Tee-Objec ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,Install-SitecoreConfiguration
Install-SitecoreConfiguration : No registration found for extension 'OutNull' of type 'Task'.
At C:\resourcefiles91\XP0-SingleDeveloper.ps1:74 char:1
+ Install-SitecoreConfiguration @singleDeveloperParams *>&1 | Tee-Objec ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,Install-SitecoreConfiguration
   
Reason:
I already have SitecoreInstallFramework version 1.2.1 installed and now I installed SitecoreInstallFramework 2.0.0.
 
After that I run the "XP0-SingleDeveloper.ps1" script and I started to receive this error.

The root cause was that PowerShell load all the available modules when its start up. If you installed any module then it will not available in PowerShell immediately.

Solution:
I just restarted PowerShell to load the newly installed module and run the "XP0-SingleDeveloper.ps1" script. This time my script completed successfully.

Happy Sitecore 9.1 Installation.