Error when creating a site from a custom template: "A
duplicate name 'FieldName' was found"
This happened to me in a client's WSS3 environment, but it
seems to apply to 2010 as well. I had a site template created
in one environment, but upon moving it to another, the Create
Site operation resulted in a neat little error, complete with
stack trace: "A duplicate name 'YourField' was found". Upon
investigating, I found that one of the lists in the
newly-created site did indeed have duplicate fields. What was
odd in this case was that the the list was based on a content
type, and only one of the duplicates came from said content
type. I deleted the extra fields, re-saved the template in the
new environment, and created again -- only to have similar
results. Several forum posts recommend cutting open the
template on your local machine, editing the XML, and
rebuilding the solution CAB, but in my case, all it took was a
quick "Delete list" followed by re-creating it and re-adding
the content type. Save as template again, and this time --
instant site creation satisfaction.