When you use the Index and Tables dialog box to update the index of your Word document, the index may be updated incorrectly. The items in the index may be updated with incorrect page numbers.
This problem may occur if both of the following conditions are true:
You use the Index tab in the Index and Tables dialog box to update the index of your Word document.
The document where you want to update the index contains sections that use different page-number formatting. For example, one section of the document uses "1,2,3.." page-number formatting, and another section of the document uses "A,B,C" page-number formatting.
In this situation, Word incorrectly changes the properties of the section that contains the index when you update the index.
To work around this problem, do not update the index by using the Index tab in the Index and Tables dialog box. Instead, click to the left of the index, and then press F9 to update the index of your document.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.