Unreal Engine 4.10 Released!

@ Sentura Did you port an older project from a different engine version over? I had similar lighting/texture problems when bringing older projects into newer versions, so I tend to stick with one engine version, or recreate from scratch if moving to a new release!


Since 4.7 materials aren’t functioning as they used to. Any reason for that?

Simply take a look at this screenshot below. With this simple setup they aren’t even compiling, and didn’t reach the limit of 16. Not even close.

4.10 have been superb so far. There is noticeable FPS boost and playing big map (~4km^2 with 14000 actors and ~2million foliage) in editor starts without big delay. Had to use small testmap before to tweak animations/AI but now its fluent also the big map. :o

so far 4.10 has really messed me up… i cant build lighting at all… tons of problems… Fails right when you click build … though swarm agent continues running with a progress bar, but the editor already failed… And if i try to use swarm coordinator with otehr agents… it will even kick me out of the unreal edtior… like instant no message crash.

Hi kurylo3d,

Have you reported this to the bug reports section of the answerhub (link in signature)? We will be able to assist you more in depth there. With your answerhub post, please include what the exact error you are seeing is, what steps you are taking to reproduce this on your end, and if you have tried this in a clean, blank project with no additional content. Additionally, check here to see if the steps provided help you:

Have you tried covering the landscape tile with a single paint layer? If so and this still does not fix the error, please post this to the answerhub in the bug reports section (link in signature) so we can assist you further. In your answerhub post, please include the image above, what steps you are taking to reproduce this on your end in a clean, blank project with no additional content, and whether you are using height blends/alpha blends on the blend node in the image provided. The resolution makes it extremely difficult to tell what each layer setup is.

This version is unstable. I am sure that I build lighting, but every time I package, it says: “Rebuild lighting! 65 unbuilt objects.” and some objects get totally bright. And there is other serious bug on mobile that may make refractional objects totally invisible. I don’t recommend anyone to work on a serious project on this version. I think Epic Games released this version too early. This should be Preview 5.

Hi Kurylo3d,

If you’re getting a crash that does not bring up the Crash Reporter window please submit the ticket on AnswerHub with the following information from this page: A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine Forums

If the editor is being closed this is likely an issue within Windows causing a crash that will generate its own Windows Error code. This error code can help determine where the crash in Windows is happening and if we can possibly help from out end.

Thank you!


Hi SalihBalkan,

Can you post a question on the AnswerHub with the issues that you’re seeing, along with repro steps and any additional information that would be helpful in replicating what you’re seeing?

When you get issues with the rebuild light warning there are several things that can cause this to happen. This is not necessarily a 4.10 issue.

You can also open up the Output Log windows (Window > Developer Tools > Output Log) and enter the console command DumpUnbuiltLightInteractions to see which assets are causing the issue. This information is more helpful in determining where the issue is.

I’m not sure off-hand about the refraction issue on Mobile that you’re describing, but please post this as a separate issue with the device you’re testing on, material setup, whether this is in editor vs device, along with any additional information that can help us look into this more quickly.

Thank you!


Hi Tim,

Can you share any updates on this: Unreal Engine 4.9 Released! - Announcements and Releases - Unreal Engine Forums

will it be fixed in 4.10 hotfixes or 4.11?


Right now, the ticket for this (UE-21858) is listed as fixed and targeting the 4.10.1 hotfix, but this ticket has yet to be verified and closed since we’ve not got a build of 4.10.1 to test on just yet. If all goes well this should be in a hot fix, but I cannot guarantee until it’s tested. If not 4.10.1 it should make 4.11.

Thanks, glad it’s fixed! :slight_smile:

It’s really sad that a such a big bug is already live for two full UE4 Versions… I’m still at 4.83 because of this bug.

Probably not the best place to post this, but I’m getting hundreds of “This map is using externally referenced packages which won’t be found when in a game and all references will be broken” map errors on every 4.7-4.9 project opened in 4.10. I never had this problem after updating to 4.8 or 4.9, so it may be relevant to this release. I’ll try to detail the issue on AnswerHub after I figure out what exact conditions trigger it, but right now I’m still trying to get rid of the errors, since the trick with renaming the project folder doesn’t seem to help.

EDIT: It seems that the errors may have been caused by changed DerivedDataCache entries in updated BaseEngine.ini, so my apologies for this premature bug report. I’m not usually the one to panic, but the sheer number of seemingly uncorrectable map errors overwhelmed me. :o



Just rename your project folder to something else and re open it from the launcher.


Edit:oooops, i didnt read until the end. My bad. Sorry.

I am currently working with someone on answers unreal to try to fix my 4.10 not able to build… getting build failed every time on any project… Even simple ones instantly…

Now i tried building MY project on another computer that allows the build to work, but when i got back to my computer it had no unreal editor open and it had a windows error about closing lightmass because not enough memory or something. Why cant you guys make a stable release???

4.8 broke screen space reflections in my project… 4.9 broke my ability to network build between multiple comps with swarm… 4.10 my main comp is build failed or a crash, and my work comp runs out of memory… 12 gb of ram… 6 gb of ram was enough to build this on another comp in 4.9…

I really think you guys need to take some manpower away from adding new sellable features… and make the engine actually WORK. I am sorry if i seem angry. I am. I am wasting way too much time and money.

PS. screenspace reflections still dont work in 4.10 for me (They are black)… and net work build i cant even test because… yea… i cant build at all.

I post on answers unreal constantly, but the only reason im posting here is to maybe… just maybe light a fire under someones a**. Thanks.

And dont get me started on performance issues… i can be in a room with 200 draw calls staring at a wall… if i move my camera back and forth while still looking at that wall… it raises to like 2000 draw calls but if i hold still it falls really quick to 200… causing massive lag spikes anywhere in my scene if i rotate the camera… as though it doesnt cull properly… and takes everything into account for a moment until u stop moving…

I fixed this by renaming my project to the original name by removing the “4.10” that the project conversion adds to the folder name.

thanks for this @everynone… good that it was mentioned :slight_smile: