# Why does UE 5.0 work but UE 5.4 crash on startup?

**URL:** <https://forums.unrealengine.com/t/why-does-ue-5-0-work-but-ue-5-4-crash-on-startup/1979555>\
**Category:** Getting Started & Setup\
**Tags:** unreal-engine, question\
**Created:** [August 17, 2024, 1:12am UTC](https://forums.unrealengine.com/t/why-does-ue-5-0-work-but-ue-5-4-crash-on-startup/1979555 "2024-08-17T01:12:26Z")\
**Posts on this page:** 1\
**Showing post:** 4

<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:** [August 17, 2024, 11:33am UTC](https://forums.unrealengine.com/t/why-does-ue-5-0-work-but-ue-5-4-crash-on-startup/1979555/4 "2024-08-17T11:33:01Z")

</div>

hi @dorusoftware ,

Looks to me like the virus check has isolated part of your installation  
Very common problem for UEFN  
[urc.exe and urc.dll get flagged as Malware from Microsoft Defender - General / Issues and Bug Reporting - Epic Developer Community Forums (unrealengine.com)](https://forums.unrealengine.com/t/urc-exe-and-urc-dll-get-flagged-as-malware-from-microsoft-defender/1802519/5)

Indicate to your virus checker that UnrealEngine.exe is safe

see [urc.exe and urc.dll get flagged as Malware from Microsoft Defender - General / Issues and Bug Reporting - Epic Developer Community Forums (unrealengine.com)](https://forums.unrealengine.com/t/urc-exe-and-urc-dll-get-flagged-as-malware-from-microsoft-defender/1802519/2)

Then If you are using Epic Launcher binary Go back and use option Verify

If you want to build 5.4.3 from a working source repository try  
[UnrealEngine-5/README.md at lgpu542 · jimshalo10/UnrealEngine-5 (github.com)](https://github.com/jimshalo10/UnrealEngine-5/blob/lgpu542/README.md)

---

_[View the full topic](https://forums.unrealengine.com/t/why-does-ue-5-0-work-but-ue-5-4-crash-on-startup/1979555)._