# UEFN crashes when linking verse devices to eachother

**URL:** <https://forums.unrealengine.com/t/uefn-crashes-when-linking-verse-devices-to-eachother/1756330>\
**Category:** Issues and Bug Reporting\
**Tags:** fortnite-creative, unreal-editor-for-fortnite, crash, bug-report, fortnite\
**Created:** [March 16, 2024, 4:06pm UTC](https://forums.unrealengine.com/t/uefn-crashes-when-linking-verse-devices-to-eachother/1756330 "2024-03-16T16:06:11Z")\
**Posts on this page:** 1\
**Showing post:** 6

<div class="post-metadata">

**Author:** ![Benjf29](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/benjf29/32/1204359_2.png) [@Benjf29](https://forums.unrealengine.com/u/Benjf29)\
**Post date:** [March 28, 2024, 1:14am UTC](https://forums.unrealengine.com/t/uefn-crashes-when-linking-verse-devices-to-eachother/1756330/6 "2024-03-28T01:14:26Z")

</div>

This probably the result of circular reference loop

This crash is produced because you declared your device as not optional

```auto
@editable
MathDev: math = math{}

```

It mean, math{} are automatically instanced, when UEFN load the file verse/ even the editable is not set.

if math contain the same declaration for the any name device, it like  
math → new instance of any name → new instance of math → new instance of any name → etc → etc → etc… finished by unreal crash.

To avoid this, you can use optional value on device declaration

```auto
@editable
MathDev : ?math = false

```

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