# UEFN crashes immediately on launch with new launcher

**URL:** <https://forums.unrealengine.com/t/uefn-crashes-immediately-on-launch-with-new-launcher/2841725>\
**Category:** Issues and Bug Reporting\
**Tags:** fortnite-creative, unreal-editor-for-fortnite, crash, bug-report, editor, fortnite\
**Created:** [October 16, 2026, 4:45pm UTC](https://forums.unrealengine.com/t/uefn-crashes-immediately-on-launch-with-new-launcher/2841725 "2026-10-16T16:45:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![valleyDweller](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/valleydweller/32/1095394_2.png) [@valleyDweller](https://forums.unrealengine.com/u/valleyDweller)\
**Post date:** [October 16, 2026, 4:45pm UTC](https://forums.unrealengine.com/t/uefn-crashes-immediately-on-launch-with-new-launcher/2841725/1 "2026-10-16T16:45:16Z")

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### Summary

Tried to open UEFN with the new launcher and it immediately crashes.

### Please select what you are reporting on:

Unreal Editor for Fortnite

### What Type of Bug are you experiencing?

UI/Tools

### Steps to Reproduce

New launcher.  
In new launcher, customize top bar, navigation, choose developer.  
Choose Projects tab in top bar.  
Try to launch a project directly from the launcher before the editor is launched. “open in UEFN”

If that doesn’t work, then just try to go back and launch the editor itself first.  
I have 42.40 from oct15.

### Expected Result

launch UEFN and automatically open project.

### Observed Result

crash

Fatal error: [File:Z:\UEVFS\Root\Engine\Source\Runtime\PakFile\Private\PakFile.cpp] [Line: 377]  
Corrupt pak index detected on pak file: ../../../FortniteGame/Content/Paks/pakChunkEarly-WindowsClient.pak

UnrealEditorFortnite\_Engine\_Win64\_Shipping  
UnrealEditorFortnite\_Engine\_Win64\_Shipping  
UnrealEditorFortnite\_Engine\_Win64\_Shipping  
UnrealEditorFortnite\_Engine\_Win64\_Shipping  
UnrealEditorFortnite\_Engine\_Win64\_Shipping  
UnrealEditorFortnite\_Engine\_Win64\_Shipping  
UnrealEditorFortnite\_Win64\_Shipping  
UnrealEditorFortnite\_Win64\_Shipping  
UnrealEditorFortnite\_Win64\_Shipping  
UnrealEditorFortnite\_Win64\_Shipping  
UnrealEditorFortnite\_Win64\_Shipping  
UnrealEditorFortnite\_Win64\_Shipping  
UnrealEditorFortnite\_Win64\_Shipping  
kernel32  
ntdll

### Platform(s)

PC

### Island Code

3438-7987-6568

### Upload an image

 ![Screenshot 2026-10-16 094346.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/d/6/3/d639a573895e3cb6a1566479bb6c35346323a28e.png)

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<div class="post-metadata">

**Author:** ![valleyDweller](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/valleydweller/32/1095394_2.png) [@valleyDweller](https://forums.unrealengine.com/u/valleyDweller)\
**Post date:** [October 16, 2026, 4:45pm UTC](https://forums.unrealengine.com/t/uefn-crashes-immediately-on-launch-with-new-launcher/2841725/2 "2026-10-16T16:45:57Z")

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Addendum: i was able to open it yesterday before the update.  
I also hit the “verify files” check and it came out OK, and rebooted, but still crashes.

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<div class="post-metadata">

**Author:** ![Jimbohalo10](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/jimbohalo10/32/961440_2.png) [@Jimbohalo10](https://forums.unrealengine.com/u/Jimbohalo10)\
**Post date:** [October 16, 2026, 9:32pm UTC](https://forums.unrealengine.com/t/uefn-crashes-immediately-on-launch-with-new-launcher/2841725/3 "2026-10-16T21:32:30Z")

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hi,

This is probably the same as this workaround that works for me. This version has loaded UEFN 42.40 on both my PC successfully

[Unable to launch fortnite through UEFN after installing the new EGL or latest update - General / Issues and Bug Reporting - Epic Developer Community Forums](https://forums.unrealengine.com/t/unable-to-launch-fortnite-through-uefn-after-installing-the-new-egl-or-latest-update/2841564/2)

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<div class="post-metadata">

**Author:** ![CosmicSkoll](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/cosmicskoll/32/1148570_2.png) [@CosmicSkoll](https://forums.unrealengine.com/u/CosmicSkoll)\
**Post date:** [October 17, 2026, 2:35pm UTC](https://forums.unrealengine.com/t/uefn-crashes-immediately-on-launch-with-new-launcher/2841725/4 "2026-10-17T14:35:15Z")

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I am running into the same issue here