The reason this happens is because of the preview pane that users use.
You have two options to fix this.
- Make people stop using the preview pane (good luck with that)
- Install the x64 version of Office
- Implement the fix below
This only happens if you have a 32-bit version of Word installed on a 64 bit Windows OS. The preview pane tries to call a handler that's not made for these versions of Windows.
The fix is rather easy and requires you to delete some registry keys, you can do this by hand or automate it by GPO or scripting. That's up to you.
- Open Registry Editor
- Navigate to HKEY_CLASSES_ROOT\CLSID
- Find the following keys and delete them completely
- {84F66100-FF7C-4fb4-B0C0-02CD7FB668FE}
- {65235197-874B-4A07-BDC5-E65EA825B718}
- {00020827-0000-0000-C000-000000000046}
- Tell the user to logoff and log back in to see if it solved the problem