# (Blocker) Cant launch a session in UEFN

**URL:** <https://forums.unrealengine.com/t/blocker-cant-launch-a-session-in-uefn/827972>\
**Category:** Issues and Bug Reporting\
**Tags:** unreal-editor-for-fortnite, question, fortnite\
**Created:** [March 27, 2023, 4:28pm UTC](https://forums.unrealengine.com/t/blocker-cant-launch-a-session-in-uefn/827972 "2023-03-27T16:28:31Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Seyuro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Seyuro](https://forums.unrealengine.com/u/Seyuro)\
**Post date:** [March 27, 2023, 4:28pm UTC](https://forums.unrealengine.com/t/blocker-cant-launch-a-session-in-uefn/827972/1 "2023-03-27T16:28:32Z")

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Whenever I want to launch a session I cant because of this: Found disallowed object type /Game/Balance/Physics/Materials/PhysData\_Foliage.PhysData\_Foliage Anybody knows how to fix it?

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**Author:** ![HalcyonKnight96](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/halcyonknight96/32/924312_2.png) [@HalcyonKnight96](https://forums.unrealengine.com/u/HalcyonKnight96)\
**Post date:** [March 27, 2023, 4:34pm UTC](https://forums.unrealengine.com/t/blocker-cant-launch-a-session-in-uefn/827972/2 "2023-03-27T16:34:32Z")

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[[Critical] Can't start a session because of validation error for "misallowed" objects](https://forums.unrealengine.com/t/critical-cant-start-a-session-because-of-validation-error-for-misallowed-objects/820029) Same issue as here. If you could DM me your project files that would be a big help.

Edit: Some more information on what you’re doing and what is in your project would be helpful too.

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**Author:** ![Wigito](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/wigito/32/1221516_2.png) [@Wigito](https://forums.unrealengine.com/u/Wigito)\
**Post date:** [April 1, 2023, 6:23pm UTC](https://forums.unrealengine.com/t/blocker-cant-launch-a-session-in-uefn/827972/3 "2023-04-01T18:23:29Z")

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Same issue, have you found the probleme ?

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**Author:** ![HalcyonKnight96](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/halcyonknight96/32/924312_2.png) [@HalcyonKnight96](https://forums.unrealengine.com/u/HalcyonKnight96)\
**Post date:** [April 1, 2023, 6:25pm UTC](https://forums.unrealengine.com/t/blocker-cant-launch-a-session-in-uefn/827972/4 "2023-04-01T18:25:34Z")

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> [@When importing buildings directly from fortnite in flying man mode the project does not pass validation and does not start giving error messages](https://forums.unrealengine.com/t/when-importing-buildings-directly-from-fortnite-in-flying-man-mode-the-project-does-not-pass-validation-and-does-not-start-giving-error-messages/832301/12):
>
> For anyone else that sees this thread with Validation errors related to Physics Materials: The issue stems from placing assets in Live Edit rather than UEFN. If you place an asset with foliage or some cloth related asset in Live Edit and then exit Live Edit you might hit this issue. My repro steps were: Open Project Launch Live-Edit Add any prefab that has an asset that references a Physics Material Logout of Live Edit (Close Fortnite client) Try to launch session in UEFN again Hit validatio…