This is an issue that I just came across and it only was affecting Excel 2003 for me. However it may happen in other MS Office 2003 applications (Word, PowerPoint, etc) as well. There may also be several different problems that cause this symptom so this resolution may or may not work for you.

I found that it was the “Open File Validation” causing the issue. I am not all that concerned with this functionality so I found a way to turn it off. This involves modifying the windows registry so if you are not familiar and/or comfortable doing so I would not recommend you trying this yourself.

1. Exit Excel

2. Click “Start Menu”, Click “Run”, type “regedit”, and then click “OK”. For Windows 7 users you may not have the “Run” option, in which case you can just type it in the search bar you see when you click on the start menu

3. Locate and select the following registry key:

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\11.0\

4. After you select the key that is specified in step 3, click on “Edit”, then “New”, then “Key”

5. Type “Excel”, and then press Enter

6. Select “Excel”, click on “Edit”, then “New”, then “Key”

7. Type “Security”, and then press Enter

8. Select “Security”, click on “Edit”, then “New”, then “Key”

9. Type “FileValidation”, and then press Enter

10. Select “FileValidation”, Click on “Edit”, then “New”, then “DWORD Value”

11. Type “EnableOnLoad”, and then press Enter (Note the default value is 0 which disables the validation.)

At this point I closed RegEdit and rebooted. I’m not 100% sure if the reboot was needed, but it never hurts.

When my PC came back up I double clicked on an .xls file on a network drive and it opened right up as it should.