[UE 4.7 R1] "Applying changes to original material and use its use in the world" 35 minutes

I’ve recently encountered this when saving materials and having to wait for a very long time. This doesn’t appear to happen all the time, but I was able to reproduce by creating a blank project, creating a material with some parameters, create an instance of said material, now edit the main material and hit apply, it doesn’t appear to happen all the time but randomly (and I do mean randomly, I can move a node to the left a bit and hit apply and it might happen) about 40% of the time it will hang there for anywhere between about a minute upto 35 minutes. This is in the initial 4.7 release

All default settings except UI was cheked, lighting mode was ‘unlit’ and it was a translucent material, but it appears to be happening with SpeedTree leaf materials as well (and probably others but I haven’t been able to test yet)

I’m using a static switch and a float as adjustable parameters.

Hey Chaoss -

Thank you for your report. Can you elaborate on the nature of the material which is causing this issue for you? What is the Material Domain, the Blend Mode, the Shading Model, if Translucent what is the Lighting Mode, is the Material Two Sided, Is it tessellated and if so, what type of tessellation, are you using a parameter with World Displacement or World Position Offset? What type of Parameters are you using Scalar, Switch, Vector? Why types of objects in the level have you applied this material to? Does the parent material yield several different instances or just one?

Let me know and Thank You Again -

Eric Ketchum

Hey Chaoss -

Under the Usage tab of the Material Attributes, you don’t want to check all of the Used with options, in general if you have the Automatically Set Usage in Editor (on by default), the material will only assign what is needed for the materials usage. If you are using the material with ALL of the Usage options, realize that each option will be processed separately in the engine which can greatly increase compile times.

Try un-checking all of the Usage check boxes and save the material again. You should have it automatically set the needed elements and will speed up your compile times.

Thank You

Eric Ketchum

I should add as well that this bug was introduced with the release version of UE4.7, I have rolled back to 4.7 preview 8 and not had the issue since.

This also corrupts the edited material and renders it unusable (editor either doesn’t see the material file in content browser, or opening the material causes the editor to crash), another thing to note is that sometimes the editor crashes anyway after chewing through all available ram (I have 64GB ram, it chewed through about 55GB before crashing).

I’m finding the release version a lot more unstable than preview 7/8

Hey Chaoss -

A few questions regarding your issue. Do you have a launcher verison of 4.7 Release and 4.7 preview 8 or are you pulling the release branch? If you are using the launcher can you give me a screenshot of your setup?

Thank You

Eric Ketchum

Hey, this remains unresolved and also happens with none-instanced materials after some time working with the editor. IT appears as though there is an unresolved memory leak somewhere in editing materials, and each time I ‘apply’ or ‘save’ the wait time gets exponentially longer until ue4 crashes

Hey Chaoss -

You may have missed my response above; Do you have a launcher version of 4.7 Release and 4.7 preview 8 or are you pulling the release branch? If you are using the launcher can you give me a screenshot of your setup?

Thank You

Eric Ketchum

Hey, I’d like to add this as resolved as the newest patch (4.7.1) appears to have corrected the issue, I was using the release version of the launcher.

The solution is to buy a 6GB / s 6GB/S SSD
move your project to ssd because the hd in which it is running windows consumes a lot of disk speed and can crash the machine or project, in ssd, unreal can use 100% ssd performance without losing performance of windows

Hey, I have the same issue, with latest (4.21) UE.

Blank project, import 2 textures, create material from (diff, png) texture, add emissive (png), save, and upon save (or apply) I get the same “Apply changes to the original material and its use in the world” message and the whole UE freezes, CPU usage is over 50%, but doesn’t appear to do anything. I’m following a tutorial video and this should be a 1 sec stuff, even in my older machine it shouldn’t take more than a few. tried restarting a few times, same result.
After the 1st texture, I left it there for 30+min, I created another one and there only seen the message for about 3 seconds.