Office 2007 now supports loading VSTO add-in’s from HKEY_LOCAL_MACHINE
Tired of making tweaks to the install package(.msi) to support “All Users” deployment in Office 2007? The GOOD news is that Microsoft has released a hotfix that enables Office 2007 to load VSTO Add-in’s from HKEY_LOCAL_MACHINE also.
Below is the KB article that has all the details
A 2007 Office system application does not load an add-in that is developed by using VSTO
https://support.microsoft.com/kb/976811
Enjoy!