I ran into a problem recently where our corporate Domino Extended Directory Catalog needed some updating and had not been refreshing data properly. The data was completely stale and hadn't been properly setup to update.
As a starting point I read this document on the IBM site about the EDC: https://www-304.ibm.com/support/docview.wss?uid=swg21093442
This was great for getting a handle on how the EDC is supposed to work, but some of the descriptions are out of date on the configuration documents.
Updating Settings
To update an existing EDC, open up theadministration client. Cick on the configuration tab, and in the left-hand navigation pane, expand "Directory Cataloger." You should check that you have entries for the appropriate filename, and times to run the task. You should also see another entry based on the EDC's Title under the "Directory Cataloger" section. This is where we'll want to make changes if we need to add new directories to aggregate etc.
Rebuilding
If you need to completely rebuild the EDC, goto the Advanced tab when viewing the Directory Cataloger><EDC TITLE> options. Click the "Clear History" button. This will force the EDC to rebuild everything completely when the task is next run. You can click on the Server tab in the Admin Client and goto the Server Tasks view to see if Directory Cataloger is currently running. If it's running and you'd like to stop it, on the server console type in "tell dircat quit". Then to force an immediate rebuild after clearing the history, type in "load dircat <EDC Filename>.nsf".
That should be it. You should see the file directory rebuilding on the server tasks view, and if inside the file by pressing F9 periodically. You will then want to manually force replication to other Domino servers holding a replica to get all the changes out into the Environment.
Also you may want to setup directory assistance if you haven't already. See this document to do so:
http://ksgnotes1.harvard.edu/help/help7_admin.nsf/f4b82fbb75e942a6852566ac0037f284/a4f6cf3dcc1e06ac852570610054b277?OpenDocument
