If you used Sales Manager Pro, you may have resynchronized a batch after an error during synchronization. In this case, some listings may be uploaded before the error is produced. If you resynchronize without removing these from the batch, they will be duplicated. We recommend checking your online account and/or email account before uploading again if you receive a synchronization error.
If you are still having trouble with this, please provide a specific example of a listing that was duplicated (both listing numbers) so that we can take a closer look.
