When opening a CMDB Configuration Item record in a form on an instance running Jakarta or later (inc. Kingston, London, M.., N..), the form may display simply "Record Not Found".
The record is clearly there, because it is shown in lists, or the display name shows up in reference fields, but as soon as you try and open it apparently disappears.
(For all other extended tables, and the CMDB before Jakarta, search for 'Record Not Found', 'Ghost Record' or 'Orphan Record' KB articles, e,g, KB0598248)
Jakarta and later. Any instance where TPP Migration has been done to the CMDB.
This KB isn't covering how the records got corrupted in the first place, but I can explain one form of this corruption:-
The underlying SQL table structure of the CMDB Extended Table was changed between Istanbul and Jakarta from Table-Per-Class (TPC) to Table-Per-Partition (TPP) methods, by applying 'Table Flattening'. This error is usually be due to a corruption of the TPP metadata, most likely a mis-match between the Class (sys_class_name) and the Sys Class Path (sys_class_path) values.
You can confirm this cause by adding the 'Class' and 'Sys Class Path'/'sys_class_path' columns to a list view, and comparing the records with similar records of the same 'Class' that do open. If you filter by a specific Class, and then Group By sys class path, you can identify the bad records easier.
The Sys Class Path field value needs correcting. This will probably require an Incident opening with Customer Support, as the fix will need doing at the SQL level.