Within Intellect, duplicate records can be found and deleted automatically though the report screen.
For instance, click on Report and select Contacts. There, simply click Find Now to find all records or run a report that finds only the subset from which you want to delete duplication.
Then, still in the Report screen, click on Edit and Find Duplicates. You can then choose to select (highlight) the newer or the older of the duplicated records. This is based on the last modified date of the record.
Once the records are actually selected, you can then hit the Delete key on your keyboard to remove them from the database.
Though this example is given for Contacts, the same can be done through the Appointment or Task Report screens as well.
Please, create a backup before attempting any mass deletion process like this.
This help article applies to Intellect 3