Failed to find game engine directory? That looks bad. Have you tried building it in editor? Whats your CPU and memory percent at in task manager when it stalls out??
hey guys! i have been unable to build the lighting on any of my scenes in any of my projects. i created a test level with just a cube and a point light and it still cannot build lighting.
build lighting works fine on another computer connected to the same network.
i have firewall disabled, and my gpu drivers are up to date.
here is a dxdiag:
[link text][1]
and some images in swarm:
i’ve noticed that it seems to be stuck on ‘Processing Mappings’.
any help appreciated! i hope this is enough information.
This happened to me too, mine gets stuck at 83% but I haven’t looked into it since.
that is a little worrying.
here is my task manager when it stalls:
my UE4 is installed on a drive other than my OS drive. do you think that’s a problem?
i’ve just been clicking “build” in ue4.
also thank you for replying.
Hello ! Same problem here 83% exactly.
same thing here, 83%…
Hey all,
Would any one you mind providing me with some simple reproducible steps so I can get this issue to occur on my end in a new blank project?
One thing you can try is to clean and validate the Swarm Agent Cache. Check to make sure you CacheFolder is empty and clean for your light build.
Let me know your results after following the suggestion or if you have further questions.
Thank you,
All I did was create the fps blueprint project, moved some of the meshes around in the default level and tried to build lighting only on preview setting. The lighting would build, then get stuck at 83% and wouldn’t do anything else. I waited a good while to see if it was just processing but the percentage wasn’t going up.
I have attempted to reproduce this issue using the steps you provided, but did not receive a crash.
Have you attempted to use the Clean option within Swarm Agent?
@dirtypaws Swarm Agent suggests the location of your cache folder be placed “on a fast drive with plenty of free space.”
You can view the location of your Swarm Agent cache folder directory by opening the Swarm Agent application from your task bar. Then click on the ‘Settings’ to view various settings for Swarm Agent.
Let me know what you discover or if you have further questions.
Regards,
I’ll give that a go when I get back to the house and see what happens
Hello !
This issue occured to me after a long time (like a week or so) without building.
I went from 4.8 top 4.9 in the meantime but it seems to me that I had the problem before updating (I thought it would be temporary at first).
I have just a scene with less than thirty arctors and a bit of particles. Nothing fancy 
I tried to clean cache and even change it’s folder, without success.
Hey all,
Would someone who is experiencing this issue be able to test a similar project in 4.8.3 to see if it occurs in that version of the engine as well?
@Cerambyx Cerdo, You say this occurred in your 4.8 project? Would you be able to test this for me to see if the same project that has the issue in 4.9, also occurs in 4.8?
Thank you,
Hey all,
I have gone ahead and entered a bug report for this issue (UE-20782).
There are other users who are experiencing and reporting this issue as well, and we appreciate your patience while we address and fix this issue. When the issue has been fixed and marked for an upcoming full release or hotfix, we will add it to our Documentation Release Notes section, or on the Announcements and Releases section on our Forums.
Thank you,
Hey Andrew, when I started downloading the 4.9.1 update yesterday I was hoping this problem would’ve been fixed. Unfortunately light building still gets stuck for me at 87% 
How is the progress on this issue?
Thanks!
Hey Slipher,
Please see my answer below in regards to updates to this issue.
Thank you,
Hi everyone,
I had the same issue in engine version 4.9.1, however it occured to me that I was able to build lighting perfectly fine a few minutes ago. So I took some steps back and it turned out that using a lightmass importance volume freezes the light building process at 83%. As soon as I delete this volume I can build perfectly fine.
After that I put a new lightmass volume in and I was still able to build lights after this step, until I started to cram the volume really tight around my scene. So maybe you guys can try to scale up the lightmass volume a bit so that it has a little bit more space, this fixed the problem for me.
Hey sandermer,
Thank you for the troubleshooting suggestions and insight, I have added your comments to the bug report in case getting a fix implemented proves to be difficult and we need further information.
Cheers,
,
I hope that you will find this useful. I posted a video to youtube showing how to create this bug. I also list the steps in the description of the video.
Thanks
Something that has worked for me is Keeping the template floor in the level, the lighting seems to rebuild for some strange reason, hope it works for you also
Hey all,
So there is no need to add more investigatory work or report this issue further. We have generated an official bug report and a fix has been implemented for an upcoming full engine release. We ask that our users remain patient while we get this integrated into the engine and pushed to a full release.
Thank you,