Had a problem the other day with content deployment. Everything was running fine then the deployment jobs started failing with an error that started out with “Duplicate content type ‘Page'” ( I wish I had the entire message but the logs have rolled over since we have fixed it). This content type was of the type ‘Page’ but it could be any of your content types.
It turns out that the content deployment jobs don’t delete the content types from the document library on the destination if they have been removed from the source. In practice if you remove them from the source site and don’t ever use them, having them on the destination isn’t really a big deal….however, if you choose to put the content type back into the document library, then you have a problem. The content deploy job attempts to push the added content type and because it already exists, it is a duplicate the the job fails.
The error message doesn’t point you to the right document lib nor does it even point you to the right site. The best thing to do is to turn on auditing of content types in the site collection audit settings on the source.
If it happens again you will be able to see the site that it happened in…in this case there are a good 12 or so sites that are being deployed and by chance the auditing was turned on so we could see where the problem was happening (otherwise, you can remove the sites and add them back in one by one until the problem occurs again).
So how do you work around it? (no not 64bit)
All you need to do is delete the content type from the document lib on the destination and run your content deployment job again, it should be successful.
Note: You should not be able to delete the content type if it is being referenced in the doc lib.
Prevention is another story. Education of the user base and limiting the number of users that can perform this function is about the only way to prevent it…but now that you know how to fix it, you should be able to minimize the downtime of your content deployments.