# Unknown extention ".umap"

**URL:** <https://forums.unrealengine.com/t/unknown-extention-umap/478393>\
**Category:** World Creation\
**Tags:** umap, unreal-engine, import, UE4, question\
**Created:** [February 7, 2021, 3:39pm UTC](https://forums.unrealengine.com/t/unknown-extention-umap/478393 "2021-02-07T15:39:40Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![venomtail](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@venomtail](https://forums.unrealengine.com/u/venomtail)\
**Post date:** [February 7, 2021, 3:39pm UTC](https://forums.unrealengine.com/t/unknown-extention-umap/478393/1 "2021-02-07T15:39:40Z")

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I needed to rename my map and after I did, it has dissapeared from my content browser however it is still in my file explorer. I have tried importing even dragging and dropping the file into content browser but all I get is an error saying “unknown extention .umap.” and one along the lines of "umap is an asset. "This is a very annoying buy and has caused me to lose hundreds of hours of work because UE can’t import a simple file.

Does anyone know how to fix this issues? Thank you.

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**Author:** ![ClockworkOcean](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/clockworkocean/32/1169999_2.png) [@ClockworkOcean](https://forums.unrealengine.com/u/ClockworkOcean)\
**Post date:** [February 7, 2021, 5:19pm UTC](https://forums.unrealengine.com/t/unknown-extention-umap/478393/2 "2021-02-07T17:19:59Z")

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Did you rename it outside UE?

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**Author:** ![bozett](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@bozett](https://forums.unrealengine.com/u/bozett)\
**Post date:** [February 13, 2022, 3:17pm UTC](https://forums.unrealengine.com/t/unknown-extention-umap/478393/3 "2022-02-13T15:17:00Z")

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I have exactly the same problem, lost weeks of work on a level… I havent renamed or updated anything, and when i open different levels on other unreal project it works fine. the problem only happens on one level. it just suddenly occured, please help !