# Uefn wont lauch ,opens then closes immediately **URL:** \ **Category:** Issues and Bug Reporting\ **Tags:** unreal-engine, fortnite-creative, unreal-editor-for-fortnite, bug-report, question, fortnite\ **Created:** [March 23, 2024, 2:45pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398 "2024-03-23T14:45:09Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![TtvCrypticqcg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@TtvCrypticqcg](https://forums.unrealengine.com/u/TtvCrypticqcg)\ **Post date:** [March 23, 2024, 2:45pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/1 "2024-03-23T14:45:09Z")
### Please select what you are reporting on: Uefn ### What Type of Bug are you experiencing? Assets ### Summary I’ve tried Verfying files Uninstalling and reinstalling epic launcher I’ve tried reinstalling windows and I tried it on both windows 10 and 11 I’ve tried everything fortnite works fine just when i run uefn I get that error I have also tried uninstalling uefn multiple times and I tried switching to a different ssd drive I have also tried it on my second pc My pc Specs are rtx 4080 and i9 13900k My second pc Specs are i5 12600k and 6650xt gpu ### Steps to Reproduce Opened Epic Games Launcher Launched UEFN The application did not open ### Expected Result To open uefn ### Observed Result it closes straight away or get error tbb.dll missing ### Platform(s) Pc ---
**Author:** ![Bug-Reporter](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/bug-reporter/32/997076_2.png) [@Bug-Reporter](https://forums.unrealengine.com/u/Bug-Reporter)\ **Post date:** [March 23, 2024, 3:31pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/2 "2024-03-23T15:31:31Z")
The status of FORT-725020 incident has been moved from ‘Needs Triage’ to ‘Needs More Info’. ---
**Author:** ![Hardcawcanary](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/hardcawcanary/32/906569_2.png) [@Hardcawcanary](https://forums.unrealengine.com/u/Hardcawcanary)\ **Post date:** [March 24, 2024, 4:22pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/3 "2024-03-24T16:22:36Z")
Heya have you got all the VC redistributables installed on your systems ? ---
**Author:** ![ckyboi1](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@ckyboi1](https://forums.unrealengine.com/u/ckyboi1)\ **Post date:** [March 24, 2024, 7:46pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/4 "2024-03-24T19:46:41Z")
what are those i cant even open it it just says running then launch or tbb.dll not found ---
**Author:** ![Levi2288](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Levi2288](https://forums.unrealengine.com/u/Levi2288)\ **Post date:** [March 24, 2024, 7:47pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/5 "2024-03-24T19:47:00Z")
Can confirm this is happening, it tries to find a dll that is missing, it is present in the FN folder. If you copy everything in UEFNS installation folder to Fortnites one the editor can startup. But ofc it will not function as it should, you will not be able to access any shared maps with teams or use revision control and so on so on… ---
**Author:** ![Hardcawcanary](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/hardcawcanary/32/906569_2.png) [@Hardcawcanary](https://forums.unrealengine.com/u/Hardcawcanary)\ **Post date:** [March 25, 2024, 1:24pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/6 "2024-03-25T13:24:45Z")
tbb.dll is a file installed by the Microsoft Visual C++ 2015 Redistributable There are so many posts about this issue, so installing it may not work. My UEFN works, but I have not installed the latest version of VC++ 2015, just one from one of my harddrives about a year old. You can get the latest from microsoft > **[Latest supported Visual C++ Redistributable downloads](https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170)** > > This article lists the download links for the latest versions of Visual C++ Redistributable packages. ---
**Author:** ![Levi2288](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Levi2288](https://forums.unrealengine.com/u/Levi2288)\ **Post date:** [March 25, 2024, 1:52pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/7 "2024-03-25T13:52:08Z")
I have all the C++ Redistributables downloaded, all of them are the latest and UEFN still doesn’t work. To make this bug happen you have to uninstall uefn and reinstall it completely, since seems like in the last UEFN update they have changed the installation path for UEFN to a separate folder, and its not in the Fortnite game folder itself. Its instead in Fortnite\_Studio under "C:\Program Files\Epic Games". If you have updated UEFN sicne the last update and did not reinstall it, the installation path stays the same (Under Fortnite directory), so you have to do a clean UEFN install. ---
**Author:** ![A1go](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@A1go](https://forums.unrealengine.com/u/A1go)\ **Post date:** [March 25, 2024, 2:52pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/8 "2024-03-25T14:52:20Z")
Hey all, we are aware of an issue with new UEFN installs not working and are looking into it right now ---
**Author:** ![Flak](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/flak/32/769441_2.png) [@Flak](https://forums.unrealengine.com/u/Flak)\ **Post date:** [March 25, 2024, 3:17pm UTC](https://forums.unrealengine.com/t/uefn-wont-lauch-opens-then-closes-immediately/1768398/9 "2024-03-25T15:17:13Z")
Link for monitoring: [Issue with New Installations of UEFN](https://forums.unrealengine.com/t/issue-with-newinstallations-of-uefn/1771613)