The Word file that you opened was selected in Windows Explorer and was appearing in the Windows preview. You then double-clicked the file to open it.
The Windows preview starts Word, which prevents the Add-In from being correctly loaded.
- End Word.
- Open the Windows Task Manager by pressing CTRL+ALT+DELETE. Click More details if necessary. In Windows 7 enable the Show processes from all users checkbox. In the list of running processes, find Winword.exe or Microsoft Word. Select the process and click End task.
- Start Word by clicking the program icon.
- On the File menu, select Open and open the Word file.