While designing or running a report, the following error is displayed:
Complete text of error message is:
The record key has been corrupted or is invalid.
This message typically occurs when an NF function references a cell or function that does not contain a record key.
The error can be resolved simply by changing the cell reference in the problematic NF function to point to a record key.
A record key is an NL function in which the field has been left blank...
... so that you can then use NF() functions to retreive individuals field values from the returned record.