Unable to start program 'c:\Program Files\Microsoft Office\root\Office16\outlook.exe' VSTO Add-In

Luis 146 Reputation points
2024-10-07T18:39:06.0766667+00:00

I'm creating an Outlook Add-In using VSTO in VS2022 and I'm getting this error: "Unable to start program 'c:\Program Files\Microsoft Office\root\Office16\outlook.exe'. The process has been terminated. Refresh the process list before attempting another attach", This happens even on a brand new empty VSTO Outlook Add-In project.

Screenshot 2024-10-07 142549

My Outlook desktop is Version 2409 Build 16.0.18025.20030 64-bit, running on Windows 11 24H2.

I tried these suggestions from Copilot:

Check Outlook Installation: It is the same path shown on the error.

Run Visual Studio as Administrator: Didn't help

Repair Office Installation: Didn't help

Check for Conflicting Add-Ins: all other add-ins disabled, same error

Update Visual Studio and Office: Up to date

Debugging Options: It stops before getting to debugger

I can't find a similar question in the usual suspects, StackOverflow, Microsoft Learn, etc. Any help on where to look?

Outlook
Outlook
A family of Microsoft email and calendar products.
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Office Development
Office Development
Office: A suite of Microsoft productivity software that supports common business tasks, including word processing, email, presentations, and data management and analysis.Development: The process of researching, productizing, and refining new or existing technologies.
4,178 questions
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