How to: Re-enable a VSTO Add-in that has been disabled
Applies to: 
Visual Studio 
Visual Studio for Mac
Note
This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
Microsoft Office applications can disable VSTO Add-ins that behave unexpectedly. If an application does not load your VSTO Add-in when you try to debug it, the application might have hard disabled or soft disabled your VSTO Add-in.
Applies to: The information in this topic applies to VSTO Add-in projects. For more information, see Features available by Office application and project type.
Hard-disabled VSTO Add-ins
Hard disabling can occur when a VSTO 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 VSTO Add-in is executing.
To re-enable a VSTO Add-in
In the application, click the File tab.
Click the ApplicationName Options button.
In the categories pane, click Add-ins.
In the details pane, verify that the VSTO Add-in appears in the Disabled Application Add-ins list.
The Name column specifies the name of the assembly, and the Location column specifies the full path of the application manifest.
In the Manage box, click Disabled Items, and then click Go.
Select the VSTO Add-in and click Enable.
Click Close.
Soft-disabled VSTO Add-ins
Soft disabling can occur when a VSTO Add-in produces an error that does not cause the application to unexpectedly close. For example, an application might soft disable a VSTO Add-in if it throws an unhandled exception while the Startup event handler is executing.
Note
When you re-enable a soft-disabled VSTO Add-in, the application immediately attempts to load the VSTO Add-in. If the problem that initially caused the application to soft disable the VSTO Add-in has not been fixed, the application will soft disable the VSTO Add-in again.
To re-enable a VSTO Add-in
In the application, click the File tab.
Click the ApplicationName Options button.
In the categories pane, click Add-ins.
In the details pane, verify that the VSTO Add-in appears in the Inactive Application Add-ins list.
The Name column specifies the name of the assembly, and the Location column specifies the full path of the application manifest.
In the Manage box, click COM Add-ins, and then click Go.
In the COM Add-Ins dialog box, select the check box next to the disabled VSTO Add-in.
Click OK.