Ever since 25.20 when I try to launch my UEFN project it gets to 79% and then just crashes. I launched the same exact map up on a different PC and it opened just fine. I feel like there is an issue right now depending on what specs you are using in your PC.
@ItzGopex Thank you for your report! We would like to look into this further, would you be able to submit a bug report using the form available here? Fortnite Creative
Just want to say Im having the exact same issue. Ever since 25.20 my project crashes at 79%. Another person on my team with similar hardware has the same issue while two others with different hardware are having no issues.
Okay after an great amount of trial and error working with another person, we finally found what caused the issue for us.
It was all caused by this tree that we had a single instance of. Best guess is the shader is causing issues on certain graphics cards.
My best advice is having someone on your team that can open the project go through and remove similar assets. After that have them push their changes and you should be able to redownload and open your project again.