rvaddon.msi is a component typically associated with the Microsoft MSDN Library installations. In the context of Visual Studio 2015
References & Further Reading:
Open Visual Studio 2015 → File → New → Project. Look for project templates under: rvaddonmsi+visual+studio+2015+download+upd
Cumulative Servicing: Apply the Cumulative Servicing Release (KB3165756) immediately after Update 3. This resolves many "elevation of privilege" vulnerabilities and stability issues. rvaddon
Q4: My build server says “Missing rvaddonmsi” even after install.
Check your system PATH. Some addons require restarting the build agent or running vsvars32.bat to expose environment variables. rvaddonmsi+visual+studio+2015+download+upd