A user account that is no longer Unix-enabled still appears in the user list when 'vastool list users' is run. Why does this account continue to appear?
The Unix attributes for the account still have values.
When you clear the "Unix-enabled" check box on the "Unix Account" tab of a user account the Unix attribute values will remain until you click "Clear Attribute Values".
Once the Unix attribute values are removed a flush of the cache will remove the user.
The vastool setattrs command can also be used to modify AD object attributes.
For the exact usage, please refer to the MAN page for vastool and look for 'vastool setattrs'. This will give you the exact options for the command, as well as some examples of usage.