Unreal Engine 4.26 released!

Just wanted to add that 4.26.1 finally fixes a really old issue on macOS with a bluetooth Xbox controller being connected :smiley:

Devs - you did not fix the Clip Length thing with the Grooms.
If slider can only go from 0-1, then 1 should NOT be an absolute value of 1cm/1 inch etc… 1 should act as 100% if slider can only go to “1”…
or let the slider go to that grooms max length #.

Like, if I bring in a groom that is max length 55, and clip length slider goes from 0-1, it is a useless slider.


  • Imagine making every light’s slider in UE4 only able to go from 0-1 candela, to where if you wanted 5, you had to type in “5” with your keyboard, otherwise candela slider would go from only 0-1.
  • Imagine every user wanting to adjust a Point Light down from 20 to 15, and when you slide it down it gets immediately clipped below 1, and sliding back up caps you at 1 candela. Everyone would complain. Why? Because it would be a nuisance. Well, that’s exactly the same phenomenon with the Clip Length as you have it now.

BUT - this is the worst, but most fascinating part, where it is exposed as an error.
When you hover over “HAIR CLIP LENGTH” it says the following:
“Normalized Hair Clip Length, ie at which the length hair will be clipped. 1 means no clipping, 0 means hairs are fully clipped.”

Well, if a Groom has a Max Length of “55”, and the slider at 1.0 represents = 1/55 = 0.01818, how can this be true then.

Because then what UE4.26.1 is saying is not true, because it should say:
“Normalized Hair Clip Length, where 0 is fully clipped, and 1 means 1.0 divided by the Max Length”

This is what you have. The math and the text do not match or make logical sense. It is an ERROR.

I like math so this is fun! But, I like Grooms more, so please please FIX.


Guys, I just wanted to apologize to @motorsep for asking a question I shouldn’t have asked.
But I submitted the bug report before doing my original post, then exactly as @acxsasx suggested I asked in this thread if anyone else had the same problem.

However, a very kind developer of the unreal engine has already answered my bug report helping me with the solution. Thank you all.

4.26.1 fixes about 6 instanced UObject issues that I have had submitted for (in some cases) years, worth the wait for .1.

LandscapeIssue2.JPG I get this error after the new update to 4.26.1. Does anyone else get this?

Hi! Need a help here for 4.26.1 raytracing, I recently shifted to UE 4.26.1 and noticed raytraced shadows are little different when compare to UE 4.25.4. Attaching couple of images here.

4.26.1 raytraced shadows

4.25.4 raytraced shadows

I have updated 4.26 to hotfix 4.26.1 but one of the plugin I need to test is currently not working with 4.26.1 so i really need to reinstall 4.26 that obviously not the list of UE versions you can install via the launcher. Any idea ?


Darn… 4.26.1 did NOT fix the GPULIGHTMASS to Android Mobile bug. Still getting the Lightmass needs to be rebuild message with bad looking maps. Screenshot included…

Prgram cant start cause api-ms-win-downlevel-kernal32 blah blah dll is missing - Feedback for Unreal Engine team - Unreal Engine Forums

didnt get that. might be a plugin thats triggering it.

they only have one xr dev. why not apply for the job? im sure steve would want some help.

no. this is why we use subversion control so you can roll back any recent changes, then download the source and compile it if you don’t like an update.
if you have your engine in a subversion you can even roll back updates to it.


see my last message about using SUBVERSION. saves huge headaches.

also you can open up swarm agent and validate the cache, could be a cache issue. try clearing the cache too. this will invalidate and rebuild all projects
chached data. i have had this fix issues before like you are having.

In the Launcher if you go to your Unreal Engine Library click the + button next to Engine Versions and it will allow you to select it.

Emissive rendering on groom assets doesn’t work at all for me.

I thought maybe it just wasn’t an intended feature but then reading this patch note in the hotfix makes me thing that it’s intended but just not working?

>>Fixed! UE-104074 Hair emissive rendering does not work when several groom are on screen

Was mentioned in the patch notes for the hotfix but I still can’t get groom assets to render emissive at all. No matter what setup I try to use it seems like emissive is just entirely disabled and the groom asset doesn’t show any change regardless of the input value I put into the emissive channel.

Does anyone know the correct workflow or settings for getting emissive to show up on a groom asset? I’ve asked on the answer hub, in the 4.26 preview thread and I even posted a bug report for the emissive channel not working on groom assets but have not gotten any responses except a few with the same question as me. I haven’t been able to find any documentation referring to emissive in groom assets either, it’s crucial for my project to have this capability or I’ll not be able to use the otherwise amazing groom rendering.

This is a major bug for us too. All our text is broken because we use RetainerBoxes with RichText widgets inside for text VFX. They display fine on fullscreen 1080p, but the size calculations are completely broken in windowed mode or any other resolution. I voted for the issue on the tracker, and it’s now the 8th highest voted 4.26 issue, but it would be nice to have some sort of acknowledgement, a plan for its fix, or at least a pointer to the cause, so we know whether upgrading to 4.26 is even viable for us.

@VictorLerp, I have confirmed that reverting this commit fixes the issue:…38935f81ceccbf
I do not see any immediate side effects, but I’m not familiar enough with the context to be 100% certain.

We are using a binary build, so for the time being I had to solve it by making our own copy of RetainerBox and SRetainerWidget, plus a reinterpret_cast hack to access the friend’ed FPaintArgs without permission, but this is not a viable path forward for most users.

4.26.1 for me after using it for awhile it develops a glitch with drop downs being the right click menu or even the variable settings they open but not visually.

4.26.1 crashes instantly (when holding the left mouse button while editing, in opposite to many left clicks) when I try to use the erosion or flattening tools on a newly created landscape. Landscape material is from MAWI.

Assertion failed: InTexture->IsAsyncCacheComplete() [File:D:/Build/++UE4/Sync/Engine/Source/Runtime/Landscape/Private/LandscapeEditInterface.cpp] [Line: 5666]

The issue now says target fix: 4.27, so that’s good news. Unreal Engine Issues and Bug Tracker (UE-107863)

Another bug we’re seeing is that the “Generate Navigation Only Around Navigation Invokers” setting no longer has any effect for static nav mesh builds, which makes nav builds take an order of magnitude longer on our setup (and also seem to ignore nav modifiers, but that’s a separate bug). We’re using this approach to build sublevel navmeshes of a large persistent level.