You receive a "File Not Found" error message in Excel when you open a file by double-clicking the file name

When you double-click a Microsoft Excel file type (.xls), Excel starts as expected, but then you may receive an error message that is similar to the following: When you click OK on the error message, the message reappears. After you repeatedly click OK, the file opens.

This behavior can occur if the Open action entry for this file type ends in %1.

If the Open action of the file type is edited and the line is restored before you press OK, a %1 is added to the registry key.

If you intentionally add a %1 to the Open action entry for this file type, a %1 is added to the registry key. If you subsequently delete the %1 from the Open action entry, the registry key remains unchanged and must be manually edited.

Additionally, this issue can occur when you manually change the file association of .xls files, or in some circumstances, when you are running multiple versions of Excel on the same computer.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
To resolve this issue, follow these steps:

1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Open the following registry key:
   HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\Open\command
4. In the right pane, click (Default).
5. On the Edit menu, click Modify.
6. Remove the %1 from the end of the Value data string so that the data string reads as follows:
   "C:\PROGRAM FILES\MICROSOFT OFFICE\OFFICE\EXCEL.EXE" /e (including the quotation marks)
7. Click OK, and then close Registry Editor.

Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.
To change the Open action of a file type, follow these steps:

1. Start the Microsoft Windows Explorer.
2. On the Tools menu, click Folder Options.
3. Click the File Types tab.
4. Click the file type that you want (that is, Microsoft Excel Worksheet) in the Registered file types list.
5. Click Advanced.
6. Under Actions, click Open, and then click Edit.
7. Make the changes that you want, and then click OK.