Excel Add In is not loaded. A runtime error occurred during the loading of the COM Add-In

Question

My VSTO Excel addin suddenly stopped working. The machine is Windows 8 x64 and i am using Excel 2010. The addin is written in visual studio 2010

Here's what i tried

The Loadbehaviour in the registry is 2. I changed it to 3 and load the addin, but still the addin is not loaded and LoadBehaviour is changed back to 2.

Added the VSTO_SUPPRESSDISPLAYALERTS environment variable and set it to 0. Added the VSTO_LOGALERTS environment variable and set ti to 1.

I restarted my excel and still addin is not loaded and i didn't get any error pop displaying the error message.

I cannot find any log file and my search for *.manifest.log resulted no results.

I am struck here and my addin is listed in inactive application addins and i can't find error why it is not active.

Please bring me out of this.

Answer 1

Did you have a chance to check out the Disabled Items list in Excel?

Microsoft Office applications can disable add-ins that behave unexpectedly. If an application does not load your add-in, the application might have hard disabled or soft disabled your add-in.

Hard disabling can occur when an add-in causes the application to close unexpectedly. It might also occur on your development computer if you stop the debugger while the Startup event handler in your add-in is executing.

Soft disabling can occur when an add-in produces an error that does not cause the application to unexpectedly close. For example, an application might soft disable an add-in if it throws an unhandled exception while the Startup event handler is executing.

When you re-enable a soft-disabled add-in, the application immediately attempts to load the add-in. If the problem that initially caused the application to soft disable the add-in has not been fixed, the application will soft disable the add-in again.

You can read more about that in the How to: Re-enable an Add-in That Has Been Disabled article.