Installing Office Customization

Question

Name: From: file:///D:/Samples/TestUpdatedVersion/bin/Debug/TestUpdatedVersion.vsto

The customization cannot be installed because another version is currently insta

Answer 1

This error can show up if you are trying to install/update a VSTO AddIn on the same machine where you've developed it, and it's caused by Visual Studio.

Whenever you build your AddIn in Visual Studio, it updates the registry key used by the AddIn thus breaking any install that you've done.

HKEY_CURRENT_USER\Software\Microsoft\Office\\Addins\\Manifest

The solution is to add a post-build event that would restore/set the registry key to the correct value. For example, if your AddIn is configured to be installed/updated from , the post-build event should be similar to:

REG ADD "HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\\Addins "
/v "Manifest" /d "" /f