Error Opening Second Workbook, Take Two

I recently featured a tip concerning an error message that may appear if you try to open a second Excel workbook by double-clicking on that workbook from within Windows. One thing I forgot to mention was that you can bypass the error condition completely if you make one small configuration change in Excel. Follow these steps:

1. Choose Options from the Tools menu. Excel displays the Options dialog box.
2. Make sure the General tab is displayed.
3. Make sure the Ignore Other Applications check box is not selected.
4. Click OK.

According to Excel's help system, if the Ignore Other Applications check box is selected, then Excel won't share DDE information with other applications. This isn't all, however--it also affects how Excel starts when you double-click on a workbook in Windows and you already have Excel open. If the option is cleared (as it should be), then Excel starts the new workbook in the current instance of Excel. If it is selected (as it may be), then Excel tries to open a second instance of itself, and you will see an error message if you have a Personal.xls file on your system.

If changing the Ignore Other Applications check box causes unforeseen problems in other ways you use Excel, then you might also consider converting your Personal.xls file to an add-in. (How to create add-ins has been covered in other issues of ExcelTips.) Add-ins are opened in a special status, akin to read-only, and can therefore be opened by more than one instance of Excel.