Lighting build failed. Swarm failed to kick off

Hello,
I have one particular map with this error recently.
On Other basic maps the light building works fine.

I searched the other similar questions :

Try copying your level assets, except the lighting into an another map and try building this new map. If this build goes successfully go back to you original map file and try building your lights again. - not helping

olved by deleting the swarm cache. You can find the cache data here: C:\Users\YourUsername\AppData\Local\UnrealEngine\4.1\Saved\Swarm\SwarmCache.Clear the cache and restart the Editor. This worked for me, allthough it doesn’t prevent swarm to crash later again. - not helping

Any other tips? :frowning:

UE 4.2.1 (+ Perforce - mymap.umap checked out.)
Also the dxdiag.txt is attached bellow for all my specs

10070-lightning+build+failed.jpg

[link text][2]

Hi VladV -

First I would suggest updating your video card drivers to 14.4 which is the current WHQL (not Beta) Display driver for your video card. Sometimes the old display drivers will cause issues with rendering builds.

Also, if you are building from GitHub I recommend recompiling the engine as well.

Let me Know -

Eric Ketchum

Ok. Drivers up to date…
Currently I’m not using GitHub,
Same problem. :frowning:

I suspect that something happened with my scene recently since other scenes work fine. But i didnd really added anything new, just installed perforce…
Is there any log where we can see what swarm’s problem is?

link textIf I open the swarm manually, same thing.
If I open the swarm with run as admin - Failed to connect to Swarm.

From taskmanager i closed the any swarm agent, then i opened again manually without admin. Run build, same error and this log file:
PLEASE check it out, I don;t understand much :(.

Using perforce, my collaborator built exactly my scene and it worked, i guess the problem should be on my pc.

9:32:57 AM: [Interface:TryOpenConnection] Local connection established

9:32:57 AM: [GetMessage] Safely returning to 5035D26D with no message

9:32:58 AM: [MaintainConnections] Local connection has closed (5035D26D)

9:32:58 AM: [MaintainConnections] Removed connection 5035D26D

9:32:58 AM: [Job] Accepted Job 03C3DCF2-4E63F598-7AB8D8A5-F6CB6CD1

9:33:18 AM: [Interface:OpenChannel] Error: System.IO.IOException: The process cannot access the file
‘C:\Users\mail_000\AppData\Local\UnrealEngine\4.2\Saved\Swarm\SwarmCache\AgentStagingArea\A6630D7233BF47B3BBCF76BB4350A2B5.FDFDF0F54249B15E8B8AA199C37B6873.mtrlgz’ because it is being used by another process.

at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)

at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)

at System.IO.FileStream…ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy)

at System.IO.FileStream…ctor(String path, FileMode mode, FileAccess access, FileShare share)

at NSwarm.FSwarmInterface.OpenChannel(String ChannelName, EChannelFlags ChannelFlags)**

(Only one swarm process is opened)

Ok.
I built de light on another computer which is more capable. It worked.
From default C:\Users\mail_000\AppData\Local\UnrealEngine\4.2\Saved\Swarm i copied SwarmCache Folder to my computer in default C:\Users\mail_001\AppData\Local\UnrealEngine\4.2\Saved\Swarm
Now lightbuilding seems to be working fine.

Thank you for the support Eric Ketchum.

Hi, I had the same issue regarding the swarm failing to initialize. I ran out of space on my C: drive, freeing more space solved the problem in my case.

Wrong Thinking to all !!!

RESOLVE ITS EASY , by another way

PROBLEM HERE " 9:33:18 AM: [Interface:OpenChannel] Error: System.IO.IOException: The process cannot access the file ‘C:\Users\mail_000\AppData\Local\UnrealEngine\4.2\Saved\Swarm\SwarmCache\AgentStagingArea\A6630D7233BF47B3BBCF76BB4350A2B5.FDFDF0F54249B15E8B8AA199C37B6873.mtrlgz’ because it is being used by another process."

  • This Means, you have two object with this same id for SWARM, for example, you copy some mesh object from content from another project to your work project, in this moment you have duplicate ID for Swarm, you must find this duplicate;

  • Its simple, look on all meshes in work project (use filtering) if you find two witch this same name, delete one of this,

  • You must of course delete all files in swarm cashe befor you RUN BUILD,

for me working all time

PS: in my case, free space not solved problem, only this method what i write, meybe after open project in another computer, ue4 or swarm don`t index all files (included duplicate by hand copy to content) or object was delete befor build, but left some index files (trash), my method save me more by 2-3 times in 100 %, this means smth its wrong with duplicate meshes (by hand copy to content).

this error was also generated when materials had same name as opposed to mesh.

@dev666rej

Hey I’m getting the same error. I have a lot of meshes in my work project that has the same names. Does this mean I have to rename all of them? That will be extremely annoying for me to do.

Is there any other solution?

You need to find the duplicate… try your luck with a swarm cache cleanup. Sometimes it worked. Other times it worked after a fresh install of UE. (just be sure to delete any file leftovers of UE)

NOT all !!!

“Its simple, look on all meshes in work project (use filtering, only mesh) if you find two witch this same name, delete one of this,”

Yes only meshes. I have approximately 400 meshes in my content folder haha. A lot of them have the same names

Just reinstalled UE4 4.7 and still did not work

for what you copy this same meshes meany times, or make this same names, its not prof. ???, first of all, we told you, what you must do to fix this, its simple, go to work, and clean this mess, its very imprtant to create all project without technical bugs, errors, 400 meshes its a like “Notihng to do” :))), i worked witch one project, where i found more than 10.000 wrong names, now its ok.

Sorry for that… I sustain dev666 theory,but, for some reason in my case it also worked with re-install or with a new update. I had this problem many times… on 2 different projects. Also keep in mind that same project with build error worked on different pc… Good luck finding duplicates…

No problem. So does this mean no mesh in the work project can have the same name? A lot of my objects have the same names but they are physically different meshes. Do I only look for meshes that are physically the same AND have same names? Or do I have to make sure every single mesh has a different name?

I believe that every mesh has to have an unique name. No matter the content. Also check not to have same name but in different folders.