Structural Synchronizer Update 2 would not uninstall and a new version would not install on top of it.
Structural Synchronizer Update 2 would not uninstall because of missing files. User tried to install Synchronizer Update 3 on top of an existing Update 2 installation and it would not install. He had to install Update 2 again and then from Control Panel > AECOsim Building Designer CONNECT Edition Update 4, click "Change" to Modify and it will install Structural Synchronizer Update 3 on top of Update 2. Update 2 was necessary to be installed first to complete Update 3. Update 3 would not install without having the previous Update 2 already installed.