Why is this group “unknown” showing up after upgrade?
If you customized the CRM 4 sitemap by adding a custom sub area to the settings area then you will get a group titled “unknownXX” after you upgrade your server to CRM 2011.
This occurs because there is no specified title for this group. The reason that you will see this only after you upgrade is because the CRM 2011 settings area is broken down into 4 new groups, whereas in CRM 4 everything was in a single group that unfortunately did not have a title. To fix this you just need to update your settings area similarly to:
Going forward if you see “unknown” for one of your other custom areas, groups or subareas you will want to double check that you have specified a title for the element.
See the SDK topic Editing the Site Map for specific information about how to edit the sitemap.