When performing a bulk load using the Data Migration tool in CRM 4.0, I ran across a huge issue on how the data is backed out. I am working on a large ACT! to CRM 4.0 migration which include 73 mapping for the Contact entity and of course, it is a trial and error process. Using the Data Migration tool is perfect since you can back out the successful records until you get a clean upload. The only problem is that the deletion process sets a flag on the entity level (DeletionStatusCode = 2) rather than actually deleting the records from the database. Then the Sync service will pick up the records for deletion and physically delete them. Now the limitation to this process is that the service will only run once a day and can not be run on demand…. until yesterday afternoon. 
Welcome ScaleGroup Job Editor! Simply install on the CRM 4.0 server and now you can actually set when the delete service runs!!
Thank you to the East Region Microsoft CRM blog. I recommend checking this blog weekly for other very useful updates to all things CRM 4.0.
