I created a new Data Comparison. I noticed that some tables were not part of the comparison, but I expected them to be. It turned out those tables had no PK set. So, I set the PK on the target tables, then Schema Comparison synched it to the target. I refreshed my Data Comparison, but the tables were still missing. I tried "tickling" the source and target settings, but it did not help. I closed the comparison and opened a new one using the "remembered" settings, and it picked up my newly eligible tables.