Examples of Good and Bad Error Messages 
The following sections list examples of bad and reformulated error messages (without comments) to illustrate the above-mentioned guidelines.
Messages Which can be Formulated More Specifically
Bad: |
Key & not in table & |
Good: |
Distribution channel & is not expected (Check your entry) |
Bad: |
The cursor is not placed on a line which can be selected |
Good: |
For the selection, position the cursor on a line of the table |
Bad: |
Release order specifications incomplete |
Good: |
Complete release order specifications by specifying order type, distribution channel |
Bad: |
List was not completely processed |
Good: |
List process cancelled at system limit (99 pages) |
Messages Formulated Less Ambiguously
Bad: |
The line & & & & is not in table 134 |
Good: |
The combination of lines input is not valid |

It would be better to explain this message in detail in a dialog box. Or it is given in the short text as above, and the reference to the individual entry fields then appears in the long text.
Bad: |
Entries incomplete |
Good: |
Complete your entries |
Bad: |
No change |
Good: |
Entries were not copied, as they already exist |

It is important to formulate the message from the point of view of the user and not from the system's perspective.
User Prompt Messages
Bad: |
Deletion flag incorrect, only 'J', 'S', ' ' allowed. |
Good: |
Enter 'J', 'S' or ' ' as deletion flags |
Bad: |
Postal code not entered or has incorrect length. |
Good: |
Enter postal code in defined length |
Bad: |
Percentage rate must be smaller than 100% |
Good: |
Enter percentage rate between 0 and 100 |
Bad: |
No items selected |
Good: |
Select items in the list first |
Bad: |
Release date entered incorrectly |
Good: |
Enter the release date in the form MM.DD.YYYY |