What can cause Outlook to change a COM-addin's LoadBehavior to 2 - other than unhandled exceptions?

Question

For some weeks now we have been fighting with an issue where at a small number of customers our Outlook addin gets unloaded and disabled for yet undetermined reasons. By \"d

Answer 1

My company has been putting up with what sounds like the same issue you are seeing for years. The plug-in we have is a VB6 COM add-in for Outlook 2003 and it’s deployed on several hundred machines that get cycled hundreds (if not thousands) of times a day. We go through the load and unload cycles a lot.

We get a fair bit of the general errors where the plug-in is loaded but not connected and we handle that in code. (Obviously not production quality)

Dim outlook As outlook.Application
Set outlook = CreateObject("Outlook.Application")
outlook.COMAddIns("MyFancyDancyPlugin").Connect = True

Rarely, but not so rare that it isn’t an annoyance, we see the plug-in reach a state where it is loaded and we can see it in “Tools>Options>Others>Advanced Options> Com Add-Ins”, but we just can’t connect to the thing. If you try to connect you don’t get an error it just switches back to disconnected. [The equivalent of switching back to a 2 in the registry key] The COM object as far as I can tell is never created. The item is not listed in the Disabled items.

We don’t actually have to redeploy to correct this error. Removing the object through the Com Add-Ins dialogue and then re-adding it there seems to correct the issue. This is still not an acceptable solution but it does get things back and running without a reinstall.

• Windows XP Professional, up-to-date patch level
• Outlook 2003 Professional, up-to-date patch level
• varying versions of McAfee Virus Scan (though disabling it has no effect - see above)
• Users are members of the local Administrators group

This seems to fit, we don't use McAfee but the virus scanner also doesn't interact with outlook or the com add-ins. We also don't use a copy protection app.

I'm sorry I can't be of more help, but I would love to root cause this.