We are investigating an issue in UEFN where the project browser may not find projects, resulting in the user being prompted to “Sync” a new copy of the project or manually “Browse” for it on disk. The prompt you see depends on whether the project is backed by revision control.
Please note your work is not lost even if you have already synced a new copy of the project. You can use the ‘Browse’ button in the project panel to find the project’s location on disk and open the copy with your latest changes. We will let you know when we have an update or a fix.