We know in outlook there are three states of a AddIn Active , Inactive , Disabled. **
** or any other method to do so.
The LoadBehavior windows registry key under the {Root}\Software\Microsoft\Office{application name}\Addins{add-in ID} key contains a bitwise combination of values that specify the run time behavior of the add-in. The lowest order bit (values 0 and 1) indicates whether the add-in is currently unloaded or loaded. Other bits indicate when the application attempts to load the add-in. See Registry Entries for Application-Level Add-Ins for more information.
Be aware, 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.