I know Microsoft publishes an article about how to do it but did not know if there were any caveats with removing a SoftDeleted mailbox prior to the retention period specified on the database. Our policy for disconnected mailboxes is 30 days. I am doing a ton of mailbox moves and starting with SP1 in 2010, any mailbox that is moved from one DB to another gets put in Disconnected Mailboxes as a SoftDelete. This ties up space on the source DB and I don't want to wait 30 days before Exchange deletes it through the normal process.
Getting rid of these SoftDeletes makes more whitespace on the source DB and keeps it from growing faster. Unfortunately there is no way to adjust the retention policy without affecting the disabled mailboxes which we want to keep for 30 days. If someone knows of a way to change the policy to only affect SoftDeleted mailboxes, let me know. Or, is there a way to move a mailbox without created a SoftDeleted copy on the source,