Error checking is not available when worksheet is protected or workbook is shared in Excel

When you enter a formula error, such as "divide by zero," in a worksheet cell, the Error Checking Smart Tag (the floating command and message box) does not appear as expected. Additionally, the Error Checking command is not available.

This behavior can occur because Error Checking is not available when the worksheet is protected or when the workbook is shared.

To make the Error Checking command available, make sure that the worksheet is unprotected and the workbook is not shared. To do so, use the appropriate method, as follows. For a Protected Worksheet

1. In Microsoft Office Excel 2007, click the Formulas tab. Error Checking is not available (appears dimmed) in the Formula Auditing group. Click the Review tab, and then click Unprotect Sheet in the Changes group.
   
   In Microsoft Office Excel 2003 and in earlier versions of Excel, Error Checking is not available (appears dimmed) on the Tools menu. On the Tools menu, point to Protection, and then click Unprotect Worksheet.
   
   Error Checking is now available.

For a Shared Workbook

1. In Microsoft Office Excel 2007, click the Formulas tab, Error Checking is not available (appears dimmed) in the Formula Auditing group. Click the Review tab, and then click Share Workbook in the Changes group.
   
   In Microsoft Office Excel 2003 and in earlier versions of Excel, the Error Checking command is not available (appears dimmed) on the Tools menu. On the Tools menu, click Share Workbook.
2. In the Share Workbook dialog box, click to clear the Allow changes by more than one user at the same time check box.
3. Click OK.
4. You are prompted with the question, "Remove the workbook from shared use?" Click Yes.
   
   The Error Checking command is now available.

In Excel 2007, worksheets can be protected by clicking the Review tab, and then clicking Protect Sheet in the Changes group.

In Excel 2003 and in earlier versions of Excel, worksheets can be protected by pointing to Protection and then clicking Protect Worksheet on the Tools menu.


In Excel 2007, workbooks can be shared by clicking the Review tab, and then clicking Share Workbook in the Changes group.

In Excel 2003 and in earlier versions of Excel, workbooks can be shared by clicking Share Workbook on the Tools menu and then clicking to select the Allow changes by more than one user at the same time check box.