These instructions assume you have opened the pdf in Adobe Acrobat Pro 2017, run its accessibility checker, and found this issue.
This issue is caused by tables within the pdf that require the cells in the header row to be marked as such. To correct this issue, first determine if you have a source document for the pdf, such as a Microsoft Word or Excel document. You will want to make as many corrections in the source document as possible. This way when you make updates to the document down the road, the issues wont re-appear and have to be corrected again.
Correcting the issue in a MS Word Source Document
- Highlight the top row of headings of the table.
- Right click and choose "Table Properties"
- Choose the "Row" tab
- Click the checkbox "Repeat as header row at the top of each page"
- Print to pdf when ready and before saving the pdf file, click the "Options" button and in the popup and make sure the "Document structure tags for accessibility" checkbox is checked.
- Save file and complete pdf creation.
Correcting the issue in a MS Excel Source Document
- Click the Page Layout tab.
- Click the small arrow for options of the "Sheet Options" area
- For the "Rows to repeat at top" field, select the icon on the right and then choose the top row of the excel sheet.
- Press Enter to confirm and return to the popup.
- Check the checkbox "Row and Column headings"
- Click OK then export you document to a pdf.
- Before saving the pdf filename, click the "Options" button and in the popup, make sure the "Document structure tags for accessibility" checkbox is checked.
- Continue with export to save pdf.
Correcting the issue in a PDF Source Document
- In the pdf, right click on the "Headings Failed" issue text and choose, "Show in tabs panel". The tabs panel appears on the left with the table tag selected.
- Click the arrow next to the table tag to open it up. You will see a list of "TR" tags.
- Select the first TR tag to ensure it is the row we need to correct. the elements of that row should highlight in the document area.
- Open the TR tag by clicking the arrow next to it.
- Each of the "TD" tags inside it need to be re-named to "TH". To do this, double click esach one, one-by-one, and renamed using the capital letters "TH"; ensuring to keep the less and greater signs on either side of it. Each tag should look like "<TH>"
- Once completed, go back to the accessibiklity errors list, right click on it and select "Check again". If successful, the error will show as green.