Error Message appearing when saving a file
 

I have the following message appear when I save one of my files:

€œExcel could not save all the data and formatting you reently added to €˜File
Name. To return to your workbook wwithout saving click Cancel. If you want
to continue saving changes without repairing the problem, Click Ok.€�

I then click on help to see what the problem is but nothing appears.

What does this message mean and how can I fix it?

Thanks,

Jane.