# Lighting build failed **URL:** \ **Category:** Rendering\ **Tags:** error, build, unreal-engine, Lighting, UE4, question\ **Created:** [October 24, 2015, 7:23pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369 "2015-10-24T19:23:24Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [October 24, 2015, 7:23pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/1 "2015-10-24T19:23:24Z")
When I try to build the level lighting, it strucks in 0% for some seconds and then it says “Lighting build failed”. I don’t know why it happens, it doesn’t happen in another level and it worked in this level some time ago. ![63981-error.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/e/5/c/e5c723bce3b4c84d09f8f9d0015d0726101e49c1.jpeg) ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [October 26, 2015, 2:44pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/2 "2015-10-26T14:44:28Z")
Hello Miki5353, In order to understand what you are experiencing I would like some more information from you. 1.) Is this a project that was made in 4.8 and then brought to 4.9? 2.) You said this does not happen in another level, does this also happen in a clean blank 4.9 project? 3.) Can you link me your DxDiag? There has been a known issue with 4.9 where light mass hangs and different percentages. If you are using windows can you open your Swarm Agent, which you can access through your taskbar, and verify that the agent is running while the build in the editor hangs? If so what you can try is opening a project in 4.10 and see if the issue still occurs there. ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [October 26, 2015, 10:02pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/3 "2015-10-26T22:02:21Z")
1. I think I created it in 4.9, but I don’t remember it well. I brought a project from 4.8, but I think it was not this project. 2. It works fine in new projects and in other maps in the same project. 3. Here it is. link text Yes, the Swarm Agent is running when I try to build the lights. Anyway if it’s not running, it automatically opens when I try to build the lights, but I recive the same error in both cases. I can also try to open it in 4.10, but I prefer not using a preview version, I will do it if there is not another solution. ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [October 27, 2015, 5:05pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/4 "2015-10-27T17:05:02Z")
There is an issue with building lighting associated with 4.9. What happens is the lightmass is building with SwarmAgent but the build either fails or just runs and sticks at different percentages. This issue has been fixed as of 4.10. If you could test this and verify that it works there. ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [October 29, 2015, 12:00pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/5 "2015-10-29T12:00:18Z")
I download the 4.10, the same problem… Lighting build failed. And there is no substance plugin for this version, so it’s another problem. ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [October 29, 2015, 1:35pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/6 "2015-10-29T13:35:55Z")
Interesting. This was with your migrated project or a fresh project in 4.10? If it was the same project I would like to test this on my end. ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [October 29, 2015, 3:58pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/7 "2015-10-29T15:58:47Z")
It was with the migrated project. ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [October 29, 2015, 5:42pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/8 "2015-10-29T17:42:01Z")
Ok, if you try and build with a clean blank project in 4.10 does it build? ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [October 29, 2015, 8:21pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/9 "2015-10-29T20:21:08Z")
It works in a clean project, I think the problem is in this map, but I don’t know what is wrong in it. ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [October 30, 2015, 2:18pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/10 "2015-10-30T14:18:16Z")
I am not quite sure either. However, as I cannot reproduce this issue and it appears that this problem is isolated to your map/project, without your unique project to test I will not be able to test this further. If you would like me to test this issue with your project please send a link to a Dropbox with your .uproject and your content and config folders. If you are uncomfortable with linking here you can go to our forums and send me a private message. What you will need to do is go to the advance search on the forums and type in my name in the “Find User” tab. ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [November 1, 2015, 9:28pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/11 "2015-11-01T21:28:48Z")
The project takes 9gb, even with 200mb of upload speed I can’t upload it… I will try it tomorrow and I will let it upload for the full day. ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [November 2, 2015, 4:01pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/12 "2015-11-02T16:01:21Z")
I just realized that I only have 2gb of space in my dropbox account (is the limit in free accounts), where should I upload the project instead of dropbox? ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [November 2, 2015, 4:08pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/13 "2015-11-02T16:08:32Z")
All I need is your content and config folders along with your .uproject files. I do not need all 9gb of the project. See if you have enough space after only adding these files. ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [November 2, 2015, 4:41pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/14 "2015-11-02T16:41:15Z")
It’s 5gb anyway, I think I imported too much assets. Should I make a copy of the project and remove some of the not used content? ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [November 2, 2015, 4:45pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/15 "2015-11-02T16:45:51Z")
Do you have another file sharing program you can link? I would like to try to get as much of your project so that I am handling as much of the project that is causing the build fail. ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [November 2, 2015, 5:05pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/16 "2015-11-02T17:05:57Z")
I don’t know where I can upload it, Mega uploads with 40kb/sec… Do you know where can I share it? ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [November 2, 2015, 6:50pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/17 "2015-11-02T18:50:32Z")
Ok, so, to help me get a further understanding and eliminate possible issues I have a few more troubleshoots for you. 1.) If you would update your drivers for your Video card. This shouldn’t make a huge difference in builds but just to eliminate this being an issue if you would go ahead make sure you have the latest version. 2.) When building your lighting, if you would bring up your swarm agent and look through your logs to see if the swarm agent is communicating with your PC and make sure there are no errors there. 3.) I will be linking you to the swarm agent troubleshooting guide to help you decipher what exactly is going on with that and what you should expect to see vs. an issue. > **[A new, community-hosted Unreal Engine Wiki](https://forums.unrealengine.com/t/a-new-community-hosted-unreal-engine-wiki/141494)** > > After over a year in maintenance mode, the official Unreal Engine Wiki is now permanently offline. These resources now live on a new community-run Unreal Engine Community Wiki — https://unrealcommunity.wiki/! You will be able to find content from... 4.) Do these first just so we can cross them off the list of possible things to cause the crash. If after these troubleshoots and taking a look at your logs then we can try and move the project file you have. ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [November 2, 2015, 6:53pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/18 "2015-11-02T18:53:22Z")
Ok, so, to help me get a further understanding and eliminate possible issues I have a few more troubleshoots for you. 1.) If you would update your drivers for your Video card. This shouldn’t make a huge difference in builds but just to eliminate this being an issue if you would go ahead make sure you have the latest version. 2.) When building your lighting, if you would bring up your swarm agent and look through your logs to see if the swarm agent is communicating with your PC and make sure there are no errors there. 3.) I will be linking you to the swarm agent troubleshooting guide to help you decipher what exactly is going on with that and what you should expect to see vs. an issue. 4.) If you would verify your 4.9 version of UE4. From the launcher next to the label that is on your engine there is a dropdown arrow next to the Launch tab. From there click on the verify option under the dropdown. Then, if that doesn’t work, try uninstalling and reinstalling that version of the engine. 5.) Do these first just so we can cross them off the list of possible things to cause the crash. If after these troubleshoots and taking a look at your logs then we can try and move the project file you have. > **[A new, community-hosted Unreal Engine Wiki](https://forums.unrealengine.com/t/a-new-community-hosted-unreal-engine-wiki/141494)** > > After over a year in maintenance mode, the official Unreal Engine Wiki is now permanently offline. These resources now live on a new community-run Unreal Engine Community Wiki — https://unrealcommunity.wiki/! You will be able to find content from... ---
**Author:** ![Guspyro](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Guspyro](https://forums.unrealengine.com/u/Guspyro)\ **Post date:** [November 2, 2015, 7:07pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/19 "2015-11-02T19:07:14Z")
I didn’t find any similar problem. I don’t recive any error log in the engine, and the common error is: Light build failed. Swarm Agent failed to kick off. But I recive: Light build failed. Here is the swarm agent error log.link text ---
**Author:** ![anonymous\_user\_cc69b907](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_cc69b907](https://forums.unrealengine.com/u/anonymous_user_cc69b907)\ **Post date:** [November 2, 2015, 7:45pm UTC](https://forums.unrealengine.com/t/lighting-build-failed/336369/20 "2015-11-02T19:45:09Z")
After pooling more knowledge from our team and taking a look at your logs we suspect that your swarm agent is failing to determine your engine directory. Troubleshoots : **IN SWARM AGENT** - Clean and then validate your Swarm Cache. In the documentation I linked above there are instructions for this. Navigate to your folder C:\Users\XXXX\AppData\Local\UnrealEngine and delete everything in this folder. The AppData is hidden by default so you will need to make this visible before you can see folders in this Window. Let me know after you have completed these two troubleshoots. If you have more than one map in your scene, and this is the only map having the issue, then perhaps it is unique to this map. From there you may be able to determine which .uasset is causing this problem. I am hoping that cleaning up your AppData, and then verifying your swarm, will eliminate this issue. [Next page](https://forums.unrealengine.com/t/lighting-build-failed/336369.md?page=2)