Please excuse the title, this was the best way I could think to describe this scenario without an entire paragraph. I am using C#. Currently I have a file server running windows server 2003 setup on a domain, we will call this oldDomain, and I have about 500 user accounts with various permissions on this server. Because of restrictions out of my control we are abandoning this domain and using another one that is more dominant within the organization, we will call this newDomain. All of the users that have accounts on oldDomain also have accounts on newDomain, but the usernames are completely different and there is no link between the two. What I am hoping to do is generate a list of all user accounts and this appropriate sid's from AD on the oldDomain, I already have this part done using dsquery and dsget. Then I will have someone go through and match all of the accounts from oldDomain to the correct username on newDomain. Ultimately leaving me with a list of sids from oldDomain and the appropriate username from newDomain. Now I am hoping to copy the file and folder permissions from the old user from oldDomain to the new user on newDomain once I join the server to newDomain. Can anyone tell me what the best way to copy permissions from the sid to the user on newDomain? There are a bunch of articles out there about copying permissions from user a to user b but I wanted to check and see what the recommended practice is here since there are a ton of directories.