Shared add-in doesn't load in Vista user account




My shared add-in (developed in C# 2005) for Excel is installed on a Vista
machine with Office 2007. Installation as administrator, specifying that the
add-in should be available for all users of the computer (registry entry in
HKLM, strongly named, no COM shim is used). It loads and works correctly in
the administrator account. But when I am switching to a user account, it
simply doesn't load in Excel 2007 anymore (add-in is faded out and unchecked,
and it says "Not loaded. A runtime error ocurred during the loading of the
COM add-in."). Investigating the case further, I found out that it doesn't
even call the Connect, OnConnection or OnStartupComplete methods of the
add-in. So there must be something outside of my add-in that makes it
stopping to load. I think some security issue...?

The add-in works perfectly on Windows XP (admin & user) and Vista (admin).
Only the Vista user account is making the troubles. Anyone any idea what the
cause might be?

Thank you so much for helping me! I appreciate your efforts.

Sanjay Dandekar

Hi Andy,

I have a suggestion on how to find out what is going wrong.

Download the process monitor utility from

Login as administrator on Vista machine and start the process monitor.
Set the filter to report events related to Excel.exe
Start Excel.exe and note that the add-in is loaded
Close Excel.exe
Save the process monitor log to a file.

Repeate the same procedure by loggin in as normal user

Compare the difference between the two logs and see where and why they are
different. This may not give you the exact problem but may help you find a
direction in which you should proceed to find the solution.

- Sanjay

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