Also see the Functions > Troubleshooting page.
One or More Invalid References
Every time I save my workbook, the following warning message keeps appearing
A formula in this worksheet contains one or more invalid references. Verify that your formulas contain a valid path, workbook, range name, and cell reference
The most common cause is an invalid reference inside a chart.
Create a new blank workbook
Select cells "A1:B6" on worksheet "Sheet1"
Enter the formula "=rand()" and press (Ctr + Enter)
Display the Insert Tab and select Column, Clustered Column to add a chart to Sheet1
Copy the chart and paste it onto "Sheet2"
Right click on the chart on Sheet2 and choose "Select Data"
Press Edit under Legend ENtries
You will see a #REF in the series values reference