When I do a query to get all users in a group like the one below (where "MyGroups" is AD Groups):
var res = from i in ctx.MyGroups
where i.Name == GroupName
The results are limited to 1500 records. I believe there is some way to get around this limitation of the Directory Searcher using the "range":
DirectorySearcher groupMember = new DirectorySearcher
It would be nice if your LINQ provider knew when it had hit 1500, then did another query for the next 1500 and so on until it had all users, then merged the results into the one list. At the moment I am going to have to try and do this manually.