Upgrade failed and now see Installation failed with error: 1638. Another version of this product is already installed. Installation of this version cannot continue. To configure or remove the existing version of this product, use Add/Remove programs on the control panel.
In Add/Remove programs in the control panel you will only see an option to change. Windows installer hung and the install is corrupt.
Download and install Windows Installer CleanUp Utility 18.104.22.168.
Once installed select the AppAssure Agent install and click remove. Go to Program Files and delete the AppRecovery folder
Run the Agent installer again.