An Orphaned contact will usually be created through in improper import or when the Account record is deleted using the datasheet grid leaving the Contact “child” item with no “Parent”.
The following error message will appear when a Contact record is opened and the Account doesn’t exist.
Refer to the “Importer/Updater” section for details on proper importing.
If however the Account is still active and the Contact is orphaned it may be possible to connect them by adding the ID of the Account to the ContactID of the Contact item. This would have to be carried out by way of the Datasheet Quick View and would be a bit time consuming if there are large numbers because first you must ascertain the ID of the Account item. If a reimport can be done it would be another option to try.
A quick way to see Orphaned Contacts is to build a View with the CompanyID field added. Sort by the CompanyID field. The empty ones will appear at the top of the list. Alternatively, you can create a View where CompanyID = blank.