Problems importing users / groups from AD

Hi There,

I am having some issues importing an AD directory. I enter all the details on the New Directory page and save, but when I run an import from the directory it begins to run and then stops with no error messages. The status message I receive states that it successfully imported 51 users and 108 groups. The problem is that my AD has at least 300 user accounts and significantly more groups. I tried temporarily switching the admin account used for the import from a standard user account to a domain admin account to ensure it wasn't a permissions issue, but no change. I'm a bit stumped as the assessment tool is obviously connecting OK as it correctly enumerates 51 accounts and 108 groups but then gives up with no error message.

Does anybody have any ideas?

Cheers

Ian