I Have photoshop photography, my installation of lightroom disappears without reason from the list of installed applications of creative cloud. I don't have uninstalled lightroom. If I click on the lightroom icon the program works perfectly
You are still running Lightroom 5.6. If you look at the application manager you will find Lightroom listed as an application to install. This will install Lightroom 5.7. If you are on Windows the installation will replace your previous version. When the installation is complete Lightroom will again be listed with the other up to date applications in the application manager.