Recently I was working with SharePoint Content Types utilizing Managed Metadata and ran into an annoying error. It simply stated "The object has been updated by another user since it was last fetched". The error is fairly straightforward, I was performing an Update() on a TaxonomyField and clearly the field was being changed before my code finished executing. However I could not find why this was happening. I was following a blog detailing how to Provisioning SharePoint 2010 Managed Metadata fields and could not see where I was straying from his example.
After hours of hunting for the answer to this I finally came across a blog talking about Fixing Taxonomy Metadata Issues After a Site Collection Restore and read one very important line "See the "Version" attribute? That was the culprit.", Low and behold I had accidentally put a Version="1" attribute in my XML of my field. I was copying/pasting one field over and over again when I was creating the Content Type and never thought anything of the version attribute when I was updating the pasted code (A new field should start at "1" right?). When I went back to the original article that I was following he also did not specify a version for his Taxonomy fields. I guess that was not an omission on the author’s part, he actually meant to not have a version on the field.
Morale of the story? Do Not Specify Versions on Fields of Type TaxonomyFieldType, unless of course you enjoy chasing your tail. Hopefully this will save someone some headaches.
Below are the links to the two blog posts, both of them are really good and worth a look if you are in need of a taxonomy reference source.