Cannot launch session; given errors that I cannot fix.

General Issues and Bug Reporting
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1

Summary

After the 35.00 update, I cannot launch session or upload a private version of my project. I am given barebones errors from uefn simply stating that my project failed to upload. It has done this for the past week.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Other

Steps to Reproduce

After the 35.00 update, I am given errors that prevent me from launching session/ launching private versions.

Expected Result

The session Should be able to launch, and private codes should be able to be created.

Observed Result

Instead, errors appear and the session/private code is unable to be created.

Platform(s)

PC

Island Code

6100-3067-4349

Upload an image

Screenshot 2025-05-09 224352.png

Additional Notes

This issue has been happening to me for the past week now, and I have been physically unable to playtest my project because of these errors.

2

hi @DRAW12 ,

Looks like your installation is corrupted

Delete directory

C:\Users\USERNAME\AppData\Local\UnrealEditorFortnite\Intermediate\ValkyrieUploadTemp

Verify installation with
How to Verify Fortnite/UEFN

3

I verified files and opened the editor to the same issues, however I didn’t delete the directory.

How should I go about deleting the directory (If that’s needed) And will it cause any harm to revision control or anything regarding my project?

Thank you!

4

Hi @DRAW12 .
This wont affect Revision Control. You are deleting intermediate temporary files which have become “locked” to UEFN and cannot be deleted because they are protected so that only you manually delete the Apps do not have privilege do wildcard deletes on a directory

you should check your disk first though

ChkDsk picture
ChkDsk picture605×445 9.32 KB

Run as Administrator
c:> chkdsk /f/r C:
yes
restart your PC and the disk will be checked (20 minutes)
If no errors or errors have been fixed
try deleting the file first

C:\Users\USERNAME\AppData\Local\UnrealEditorFortnite\Intermediate\ValkyrieUploadTemp\2cd13d7f-4475-6439-71c6-f9956e9e8d9c\runic.zip

Normally the directory ValkyrieUploadTemp does not exist only during cooking and transfer.

5

So I have some questions on this and some further information I want to give:

  • Friends on different (Lower spec) computers were able to launch session and private version just fine. So this leads me to think you’re right on this.

  • I downloaded the entire project on my laptop (UEFN and Fortnite was already installed on there) to see if there were issues from there, it still gave the same exact errors.

Can a download be corrupted from the same windows account on two different devices?

I really appreciate your help. Do you think you could also better reference the process of what I need to do for deleting the directory?

6

hi @DRAW12
If you have another version on a laptop and you are using Revision control.
Remove your copy of the project you put on the laptop.
Restore it from Unreal Revision Control to sync your project on the laptop.

see the documentation. see URC Sync changes

This will bring down a new copy of your project, then you can try and run your project
You don’t need to try and delete the file on the laptop.

7

Hello,

I had forgotten to mention that I had only used my laptop as a means of testing if the project would work on another device, aside from my desktop.

For the process you mentioned, deleting my copy and syncing to latest with revision control, I have already tried this on my desktop and received the same errors.

Why are my friends able to launch sessions on their computers, but I cannot launch session (Even after redownloading the project) on either of mine?

8

Hi @DRAW12
Just seen this known problem with cooking some islands not cooking
We are investigating an issue in UEFN where some projects are failing to cook. We’ll follow up as soon as we have a fix or more information.