Hi Hmcll,
Do you currently have access to the launcher or is the the launcher not even opening? If you have access to the launcher, try removing the problem project from the Unreal Projects folder in your Documents temporarily and see if you can launch the current version of the editor. If not, select the current version of the editor in your library and from the drop down menu select, “Verify.” Let us know if this works or if you do not even have access to the Launcher.
Thanks,