Export-spweb / Import-spweb leaves the lookup columns empty

Question

The export / import operations seems to be working quite well except for lookup columns. The lookup columns and other columns associated with the lookup are all empty.

Is this a limitation? Is there any script or tool that can overcome this?

Here's my code:

#This is the source web that is hosting the lists to move
$sourceWebUrl = "http://servername/subsite"     
#This is the destination web, where the lists will be copied to
$destWebUrl = "http://servername/sites/subsite"

#Location to store the export file
$path = "\\servername\Backups\"

#comma delimited list of List Names to copy
$lists = @("list2", "list1")


#Loop through the lists, export the list from the source, and import the list into the destination
foreach($list in $lists)
{
  "Exporting " + $sourceWebUrl + "/lists/" + $list

  export-spweb $sourceWebUrl -ItemUrl ("lists/" + $list) -IncludeUserSecurity -IncludeVersions All -path ($path + $list + ".cmp") -nologfile

  "Exporting complete."



  "Importing " + $destWebUrl + "/lists/" + $list

  import-spweb $destWebUrl -IncludeUserSecurity -path ($path + $list + ".cmp") -nologfile

  "Importing Complete"
  "`r`n`r`n"
 }

Source taken from http://blogs.msdn.com/b/jorman/archive/2011/01/08/copying-lists-with-powershell-in-sharepoint-2010.aspx

Answer 1

After migration lookup columns lost relations because list GUIDs they are using are different. This cannot be avoided and this is main disadvantage of using export/import based migration.

Here you can find known issues when using import/export:

• Migration Ugliness - SharePoint 2010 Content Migration Limitations

Answer 2

I have had the same problem (empty lookup fields) after importing libraries. But I could easily solve this problem by changing the order of importing the libraries. At firts I had to import the library which was referenced by the others. Of course this works best with a limited number of libraries, so that you have an overview of which library is referenced by another one.

Hope this helps,

many greetings from Bavaria (Oktoberfest is over now :-() )

Max