Powershell script to Export and Import Managed Metadata Termstore across SharePoint farms while still retaining its GUIDs

While migrating your site collections from one farm to the other, Managed Metadata termsets being used and stored in lists and libraries for various site collections would reference to the GUID’s of the original managed metadata term store. The site columns themselves, would reference the GUID of the term sets of the source managed metadata service. Hence, it becomes difficult to migrate the various site collections to the new farm. In this situation, we run the risk of making the existing managed metadata columns being orphaned for the source site collection to be migrated.

Below mentioned PowerShell script Exports and Imports Managed Metadata termstore still retaining its GUID's (sspId's- used internally by the Termstore) and referred by Managed metadata columns in list/library.

#Export Managed Metadata Taxonomy Name

$managedMetadataAppSource = “4a867ce5-d9ee-4051-8e73-c5eca4158bcd”; #this sets the exporting MMS ID
$mmSourceProxy = Get-SPServiceApplicationProxy | ?{$_.TypeName -eq "Managed Metadata Service Connection"};
Export-SPMetadataWebServicePartitionData -Identity $managedMetadataAppSource -ServiceProxy $mmSourceProxy -Path "C:\ExportManagedMetadata\locationexportfile.bak";

#Import Managed Metadata Taxonomy Name

$managedMetadataAppTarget = "d045d3ce-e947-4465-b039-0dfbbe24fb22"   #this sets the importing MMS ID
$mmTargetProxy = Get-SPServiceApplicationProxy | ?{$_.TypeName -eq "Managed Metadata Service Connection"};
Import-SPMetadataWebServicePartitionData -Identity $managedMetadataAppTarget -ServiceProxy $mmTargetProxy -Path "C:\ImportManagedMetadata\locationexportfile.bak" -OverwriteExisting;