After installing the git application, the warnings are gone so the build is without any problem.
But when I click on the running the OSGi for [io.openems.edge.application] the same error appears (Error: Could not find or load main class Mansoor\git\openems\io.openems.edge.application\generated\launch5567575842129602249.properties).
Somehow there is some class file which is not letting run the application.
it looks to me, that you have some problems with your git installation. Please check if your git is installed properly and that it is reachable from windows command line. To do so you can press <win>-r and type “cmd” in the input field and start it. Then type “git”. You should now see the git command line help output. If you got back an error here, your git is not installed properly.
Either GitHub Desktop does not provide a git command line utility or it is not added to your system path correctly. I do not know GitHub Desktop. I am using Git and TortoiseGit for Windows. After installing them and rebooting the system I can use git from the command line.