Office Compatibility Pack SP2 screws file associations

Our testing of the compatibility pack SP2 shows that installing it via WSUS
changes the default association for docx files from winword.exe to moc.exe.
This means that a user trying to open a docx file by double-clicking on it in
Windows Explorer or as an Outlook attachment gets an error message saying
that the file cannot be found. Using Windows Explorer to change the default
association back to winword.exe fixes the problem.

Workstations still running the compatibility pack SP1 don't have the problem.

Nick Payne

If the .docx extension is mapped to WINWORD.EXE then it appears that you have
Word 2007 installed and you don't need the Office Compatibility Pack.
Uninstall it and repair Office. (This is assuming you have an Office 2007
suite installed and not just Word 2007 standalone mixed with Excel 2003
and/or PoerPoint 2003).

We had the same issue as Nick. After installing the compatibility pack SP1
or SP2, it broke the file association with office 2007 file types. I
contacted MS and they said it was a known issue with installing the the
original compatibility pack, then upgrading our office 2003 install to SP3,
then installing the compatibility pack SP. Something about that installation
order does not maintain the file associations.

I tested both scenarios, installing SP3 for Office 2003 before installing
the Office 2007 compatibility pack and then compatibility pack SP did not
break the file associations.