What worked for me, is i right clicked the UPROJECT file in the file explorer, and i set its default app to the UE4Editor.exe under the unreal install. (It’s just “UnrealEditor.exe” for UE5.6 and likely just UE5 versions in general.)
UE_4.27\Engine\Binaries\Win64\UE4Editor.exe
!!! BIG WARNING PLEASE READ !!!:If you switch engine versions, set the default back to the basic “Unreal Engine Version Selector.exe” located in\Epic Games\Launcher\Engine\Binaries\Win64. I do not want people possibly bricking their projects by forgetting to switch it back**.**
It also seems like a lot of people are having this issue and it might be due to a update to epics launcher, it almost certainty has to do with the unrealversionselector executable. Hopefully epic soon fixes this.
I’m surprised someone already ran into this problem shortly after i posted my solution lol, i am glad it worked but have no idea why its even a problem. I compiled a blueprint, it got hung up so i ended unreal in task manager and it started giving me this problem until i applied the fix i found above.
I got this “failed to launch editor” out out of nowhere today.
Found couple of threads on reddit and unreal forums. But there were either no solutions posted, dead links, or “I just formatted my entire drive and it helped”.
Re-installing the engine and verifying did nothing either.
!!! BIG WARNING PLEASE READ !!!: If you switch engine versions, set the default back to the basic “Unreal Engine Version Selector.exe” located in \Epic Games\Launcher\Engine\Binaries\Win64. I do not want people possibly bricking their projects by forgetting to switch it back**.**