How can I fix “There was a problem sending the command to the program” in Excel?

Question

I'm running Microsoft Excel 2007 on a 32-bit Windows 7 install. As of yesterday, when I try to open an Excel file from the desktop/Windows Explorer, Excel starts and displays the error

There was a problem sending the command to the program.

but does not open the file. I can open the file by double-clicking it again.

My searching shows that there are three main causes of this problem:

1. Ignore other applications that use Dynamic Data Exchange must be unchecked, as described in this SU answer and elsewhere
2. ZoneAlarm settings may need to be tweaked per this forum post
3. Compatibility settings need to be disabled, per this SU answer

Ignoring other apps was already unchecked for me, ZoneAlarm is not and never was intalled on my machine, and I wasn't using any compatibility settings. What else could be the problem? The file itself? The file came from another computer, which I trust but don't have access to right at the moment.

Answer 1

This is a pretty well known bug in how Windows 7 implements the preview pane in explorer. Go back and look and I bet the preview pane is on. The simple fix is to turn it off. Very few people want it on. Another fix is to alter the user process so that each time Excel is run, a new instance is created. Most people don't work that way but if you open Excel first and THEN browse to the file then you will not see this error. You may see some people mentioning to turn off the DDE feature but this actually breaks copy/paste between instances.