E-File Validation Errors are special, specific, and often vague errors that you can receive even after you've run Diagnostics and no errors were found. Sometimes you can click on them, and they will usually take you to the form that's having an issue. Keep in mind that if you have multiple copies of the same form, it may not always take you to the specific form with the issue, so be sure to check all relevant forms.
Below is an example of an e-file validation error you may come across, and how to resolve it.
This begins with InCareOfNm, which gives us a small clue as to what line is experiencing an issue. The next term The value 'FIRST LAST' tells us which text is wrong. If the value is '' that typically means there is missing information in the referenced field. So for this error, we know to look at the Name Line 2 field on the Main Information sheet.
Now in this example, the referenced text FIRST LAST is incorrect. It is incorrect because on the Name Line 2 field, names must be entered in a specific format. The name should be entered as % FIRST LAST.