The Blackbaud Excel Add-in allows users to connect to query data from within Excel. When attempting to re-install the Blackbaud Excel Add-in after previously uninstalling it, a user may receive Error: System.Deployment.Application.DeploymentException: Unable to install this application because an application with the same identity is already installed. To install this application, either modify the manifest version for this application or uninstall the preexisting application.
at Microsoft.VisualStudio.Tools.Applications.Deployment.ClickOnceAddInDeploymentManager.DownloadAddIn(TimeSpan timeout)
To resolve this issue, clear your local application cache before trying to re-install.