Hey there @Ragnar-793! Welcome to the community! I can’t seem to recreate the issue on my side. To get a better idea of what’s happening, I have a couple questions.
When you say that every C++ project “Can’t be opened anymore”, how does that present? Does it quietly fail, freeze, or produce an error?
Can the projects be launched from their respective uProject files?
Can you try to verify the integrity of the 4.27 installation in the Epic Games Launcher?
Edit: It seems this issue may have a workaround discovered by another user on this thread: