I had over 85GBytes of UE4 engines and data installed on my external USB3 drive when my computer decided to lockup and bluescreen. No problem, right? Everything was installed externally. No such luck. The launcher would not work when I plugged the external drive into another computer, and there was no repair function. I ended up spending two hours tricking the launcher into reinstalling itself. Once that was done, it refused to use the Gigabytes of UE4 engines that were already downloaded. Its been almost 24 hours, and I now have some of my engines re-downloaded and working.
Good news-- my computer is coming back from repair and I have to give up this less-powerful loaner. How can I continue to work with UE4 without spending another long day reinstalling everything?
If I really can’t avoid reinstalling, can I save the files somehow so I don’t have to download again, as well as install?
Redownload is probably only solution here, alternatively you could try to set UE install location where the existing engine is, laucher then might download only things it’s missing.
Note that you don’t need to use launcher at all or else you use something from marketplace then you need at one binery installation from launcher. UE4 has it own project selector so all you need to do is is run , you can also load project by double click uproject file. To fix up *.uproject assignment, take UnrealVersionSelector.exe from laucher binery forder, copy it to binery forder of your engine and run it, it will as you if you want to register this installation of engine, you say yes. After that if uproject still dont work, right click uproject file and select “Switch Unreal Engine version…” and select regiistered engine, this sould make it work. Not sure if this oprtation will solve laucher but who knows, but it will make enigne usable, you just need to run it without laucher or start up project by opening uproject file.
I primerly work with GitHub builds of UE4 and i rarely run Epic laucher and never been annoyed by this workflow.
your going to have to re-download. also i would bet the reason unreal didnt work on your second computer is because it didnt have the data needed in the registry. all your really going to need to do is redownload the launcher and the engine version your using. your projects will still be good. once you have the editor working again just migrate the projects or go to their location on the drive and open them to add them to the library.