Trying to import a Citrix Storefront Config produces the following Error

Import-STFConfiguration : An error occurred configuring StoreFront diagnostics. Method invocation failed because
[System.Collections.Hashtable+ValueCollection] does not contain a method named ‘Contains’.
At line:1 char:1
+ Import-STFConfiguration -configurationZip “c:\Temp\backup.zip” -HostB …
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Import-STFConfiguration], Exception
+ FullyQualifiedErrorId : System.Management.Automation.CmdletInvocationException,Citrix.StoreFront.ImportConfigura
tion

You need to wipe your Storefront Config using the below Commands

PS C:\Program Files\Citrix\Receiver StoreFront\Scripts> . .\ImportModules.ps1
PS C:\Program Files\Citrix\Receiver StoreFront\Scripts> Clear-DSConfiguration

Then retry import

I got then next error

Import-STFConfiguration : An error occurred configuring StoreFront diagnostics. The running command stopped because
the preference variable “ErrorActionPreference” or common parameter is set to Stop: Cannot remove item C:\Program
Files\Citrix\Receiver StoreFront\Receiver Clients\Mac\CitrixReceiver.dmg: You do not have sufficient access rights to
perform this operation.
At line:1 char:1
+ Import-STFConfiguration -configurationZip “c:\Temp\backup.zip” -HostB …
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Import-STFConfiguration], Exception
+ FullyQualifiedErrorId : System.Management.Automation.ActionPreferenceStopException,Citrix.StoreFront.ImportConfi
guration

Deleting 

C:\Program Files\Citrix\Receiver StoreFront\Receiver Clients\Mac

and 

C:\Program Files\Citrix\Receiver StoreFront\Receiver Clients\Windows

fixed this