Problem instaling outlook add-in in Office 2013


I am developing an add-in for outlook that references other libraries. It is supposed to work in Office 2013 and 2016 but in 2013 it does not work.

Showing the errors the only thing I found is this:

LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Users\Popp\AppData\Local\Apps\2.0\JW01D5OR.8RE\ROEMLG7C.9LB\outl..vsto_d09fd7cbd513af1b_0001.0000_635810ba53eccad0\OutlookAddIn.dll.config
LOG: Using host configuration file:
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Users/Popp/AppData/Local/Apps/2.0/JW01D5OR.8RE/ROEMLG7C.9LB/outl..vsto_d09fd7cbd513af1b_0001.0000_635810ba53eccad0/MyLibrary.DLL.
ERR: Failed to complete setup of assembly (hr = 0x8007000b). Probing terminated. 

The .Net version is installed fine.

asked on Stack Overflow Jun 10, 2019 by Aragorn

1 Answer


There are a lot of reasons why your add-in may not work in Outlook. I'd suggest starting from checking dependencies whether any platform specific components are used, for example, x86 assembly can't be run in Outlook 2013 x64 (and the opposite). So, first of all, you just need to make sure everything is deployed correctly. Then you may check the windows registry keys for the add-in - whether Outlook can detect the add-in and load it. If your add-in is supposed to be loaded at application startup, look at the LoadBehavior for your Add-In in the windows registry and make sure it is set to 3. This is necessary because, whenever an Add-In load fails, Office disconnects the Add-In (Loadbehavior changes to 2).

Hard disabling can occur when a 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 a 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. Read more about that in the How to: Re-enable a VSTO Add-in that has been disabled article.

Also, you may find the Troubleshooting COM Add-In load failures article helpful.

answered on Stack Overflow Jun 12, 2019 by Eugene Astafiev

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