I wouldn't go as far as saying that the installer has "a bug or two", since I've upgraded about 20 or so VBox installations without a hiccup. An aborted installation can be a symptom of the diagonal sign that you saw.soundg wrote:This would lead me to think the installer for VirtualBox has a bug...or two...when it comes to installing a newer version when you already have an existing version installed.
Simply deleting the VirtualBox.app does not uninstall it completely because there are other files and services that are installed in the system folders. The proper uninstallation procedure is to use the "VirtualBox_Uninstall.tool" found in the DMG that you installed VirtualBox from.