I am using sp2010. When I go to the site columns page of the site below (http://myCompany.com/sites/archive/_layouts/mngfield.aspx) I got this error:
Field type CrossSiteLookup is not installed properly. Go to the list settings page to delete this field.
I did empty already the recycle bin.
What can I do to fix this?
UPDATE Someone told me, this sharepoint portal was before sp2007. There was a third party wsp installed which installed this custom field type "CrossSiteLookup". The sharepoint portal is migrated from sp2007 to sp2010, but the wsp isnt migrated. So at this moment the custom field type is not available. There is a column which is refered to this custom field type. I try to remove it in powershell but get the same error.
Do I need to deploy this custom field type to make it possible to remove the column which is refered to this custom field type?