SDL Tridion 2013 SP1 Content Porting Import Error - [Error] System.Xml.XPath.XPathException: Namespace prefix 'ns2' is not defined

Question

Has anyone ever experienced this error below on a Content Porter import before?

After a successful export, I have been able to identify that these are component and/or schema specific, for example, I get the error on just one component within the entire folder I am working in that contains 50 other items, this is how I drilled down to the specific component with a specific schema throwing this error on import

I can also open, save and close, publish the component correctly from the CM I exported out of and see no visible explanations of why it would have this error associated with it.

I think it is somehow schema related, but everything is working fine in our lower environments. This is the 1st CP into a new TCM with this environment setup.

[Error] System.Xml.XPath.XPathException: Namespace prefix 'ns2' is not defined. 
  at MS.Internal.Xml.XPath.CompiledXpathExpr.UndefinedXsltContext.LookupNamespace(String prefix)
  at MS.Internal.Xml.XPath.BaseAxisQuery.SetXsltContext(XsltContext context)
  at MS.Internal.Xml.XPath.FilterQuery.SetXsltContext(XsltContext input)
  at MS.Internal.Xml.XPath.MergeFilterQuery.SetXsltContext(XsltContext xsltContext)
  at MS.Internal.Xml.XPath.CompiledXpathExpr.SetContext(IXmlNamespaceResolver nsResolver)
  at System.Xml.XmlNode.SelectSingleNode(String xpath, XmlNamespaceManager nsmgr)
  at Tridion.ContentManager.ImportExport.ImportItemPreProcessor2013.PatchXLinks(IdentifiableObjectData item, PackageItem packageItem, IEnumerable`1 cutDependencies)
  at Tridion.ContentManager.ImportExport.ImportItemPreProcessor2013.ConvertToDataObject(PackageItem packageItem, IEnumerable`1 dependenciesToCut)
  at Tridion.ContentManager.ImportExport.ImportItemPreProcessor.GetDataObject(PackageItem packageItem, IEnumerable`1 dependenciesToCut, ImportAction action)
  at Tridion.ContentManager.ImportExport.AbortErrorHandler.Invoke[T](Func`2 function, LocalizableMessage message, Boolean retryAvailable, Boolean isCritical, UserReply additionalUserReplyOptions)
  at Tridion.ContentManager.ImportExport.Importer.GetImportItemData(WebDavUrl exportUrl, Dictionary`2 unresolvedDependencies, PackageItem packageItem, ImportAction importAction)
  at Tridion.ContentManager.ImportExport.Importer.ImportItem(WebDavUrl exportUrl, IList`1 dependentItemsChain, Dictionary`2 unresolvedDependencies, Boolean specialImport)
  at Tridion.ContentManager.ImportExport.Importer.ImportItems(IList`1 items, Boolean specialGroupImport)
  at Tridion.ContentManager.ImportExport.Importer.Import(String packageName)
2015/04/22 15:32:56  [Information] Transactional import failed at 4/22/2015 3:32:56 PM. No changes were committed to Tridion Content Manager.

I also notice that within the environment I am exporting from, the component when I view source contains all namespaces, whereas, the TCM I have done the import into, only contains one namespace for all components I open and check source on - below are just 2 examples had to remove opening tags on xml

Module xmlns="http://abc.xxxxx.com/example/somename/Module" xmlns:ns2="http://www.w3.org/1999/xlink" xmlns:ns3="http://www.tridion.com/ContentManager/5.0/Instance">

Module xmlns="http://abc.xxxxx.com/example/somename/Module">

Answer 1

After a lot of content porting with the same error, I watched what specific items would import successfully, and from there I knew it was related to a specific component type that was based upon a specific schema. So with that understanding, and looking into the .xml export files, I remember the person who created the schemas changed the namespaces to reflect best practice to be http://mycomany/schemas/myfolderschema @EricHuiza outlined here.

In the same article within the answer of the SE thread above, I noticed what @NunoLinhares said in his answer about: You do have to be careful when changing namespaces on a schema that is already in use, as this will invalidate existing content (content will not be valid according to schema).

So I looked the whole way back to our Dev environment where the schemas were 1st created, did a version history, compared versions with each other and wahlah, the person who initially created the schemas went back and changed the namespace to http://mycomany/schemas/myfolderschema from a uuid:123 after content was migrated via Core Services, hence the namespace throwing an error on all components associated with that schema and even dependencies of it..

One thing I have learned with Content Porter is that it exposes anything wrong with your implementation.. Some people hate CP, but I think I love it :)

Answer 2

It would appear that the schemas are not identical between your exporting and importing environments. How this has happened should be a matter of further investigation (to prevent future similar issues) but a solution could be to also export the schema in content porter and importing the schema first.