Problem Summary. When searching the Apple Address book for an entry (record), some entries do not show up in the search results.
Problem Cause. The problem may be caused by using iSync through .Mac with multiple computers that are on different versions of OSX such as one using Leopard and the other using Tiger. The .Mac service seems to have been recently upgraded to work with the new Leopard features. This could make it difficult to synchronize between two slightly different data structures. There could be an index file that speeds up searching of the contacts in the Address book. This index file may get damaged or corrupted. Older records, that haven’t been modified, might not be effected by this issue since synchronizing would not change them in .Mac or on any of the synchronized computers. This does not seem to effect the Spotlight search index.
Problem Solution. If the entry can be found by scrolling the list alphabetically, then edit the entry (add something and then remove it) then save it. It should now show up when performing a search. If the record cannot be found by scrolling the contacts alphabetically, it may be possible to find it using Spotlight. Then edit the record.
Additional Resources. Below are additional resources to resolve this problem.