Massive Issues with Moving Files

Hey there

This has been a problem since Beta and seems to still be a prominent issue in the Unreal Engine 4:

Moving Files from one folder to another internally using Unreal Engine 4 takes an enormous amount of time!

Why is this?? This seems to have been a consistent problem since forever in the Unreal Engine. My computer, running Windows 10, can move the same files in less than a second. Unreal Engine crashes after having tried to move a couple folders and the content inside for about 15-20 minutes.

My computer alarms me, saying that UE4 is using a huge amount of RAM and perhaps I should shut it down. Then I say “Cancel” to that and the engine is still running, slaving along as it tries to move files. Then suddenly, the engine crashes and both of my screens starts turning on and off several times, before the focus comes back on and several programs have crashed, most likely due to RAM issues.

Only UE4 does this. No other program on my computer does this AT ALL. To give you an example of what I tried to move, I went and made a new blueprint project with UE 4.14. Just the FPS template. Then I went ahead and added your kite demo assets to the project (which is 4.13 but there should be no issues otherwise I assumed). Then when the files were added, I wanted to adapt what was added to my own file structure and that included moving everything in the Environment Folder into another folder that I made.

Trying to make UE4 do this, will make the engine crash after attempting to move the files for about 15-20 minutes.

I repeat this has been a problem since day one of this iteration of the engine. Some needs to take a serious look at how UE4 relocates files and references because it’s not working out.

My specs:

  • Windows 10 Home 64-bit
  • System Manufacturer: ASUS
  • Intel Core i7-4790K CPU @ 4.00 Ghz (8 CPUs), ~4.0GHZ
  • 16384 MB RAM
  • NVIDIA GeForce GTX 980

Please make it your mission to look into this because it’s getting silly at this point :confused:

Hi Vipar,

Sorry to hear you are having issues when moving assets from folder to folder in the Content Browser. In order to examine this as a bug, however, we have to isolate a few factors that otherwise produce a false positive for a bug.

For example, in your sample you are using the UE 4.13 Kite Demo assets in UE 4.14, assuming there would not be a problem. This is not necessarily so; With each new iteration of the engine the fixes that are made are not necessarily backwards compatible with previous versions of the Engine. In short, in order to test this correctly you either need to have 4.13 Kite Demo assets open in 4.13 or 4.14 Kite Demo assets open in UE 4.14. Please test this way and let me know if you are experiencing a crash.

Also, be advised that the reason files do not simply move from one location to the next as easily as other programs is that UE4 is creating and leaving Redirectors in the original location. As it states in the documentation on Redirectors,

This is so that packages that are not currently loaded, but reference this asset, will know where to find it in its new location. Choosing a naming system early on and sticking with it will avoid many of the problems experienced with Redirectors.

These two issues, coupled with the fact that the Kite Demo is our most massive and intensive sample with all the assets redirecting new reference locations, etc. it is not surprising to see a crash on a single system when the demo itself was built across multiple machines using a sophisticated file management system across a network.

All that said, if still feel there is a bug present, please recreate the bug in one of the Starter templates using the provided starter content, list your repro steps and, if we can reproduce the issue on this end, we will enter a bug report to ensure the issue receives appropriate attention.


Just made a completely blank Blueprint project with 4.13.2 and then added the 4.13 Open World Demo assets to it (like in my original project). Then I went into the “Environment” folder and marked all the folders in there. Then I dragged them into my “Landscape” folder and it happened again. The computer sits around forever where nothing happens and eventually the engine crashes (even the report tool crashes).

Then I tried moving them folder by folder. It still took forever to do this but eventually I got to move most of it. However, when I tried to move the Trees folder, it locked up again and after a while it crashed.

The essence of the problem here is still that it takes a massive amount of time to move large quantities of files (and apparently something is bugged about your speed trees?). I don’t know how UE4 does this internally (though I did know of the existence of Redirectors), but just to take an example from a competitor: Moving large amount of data around in the Unity Editor works at the same speed that moving files around in Windows does which means it goes very fast. I don’t know what they do that you don’t but looking at it could perhaps help? (Not trying to say you don’t know how to do your jobs, genuinely just a suggestion)

Hi Vipar,

We’ve been looking into this and while I can see that Kite Demo assets, which make extensive use of Speedtree and 8K textures, when moving them from the Environment to a custom folder, will max out the memory on a typical work station we do not find this to be the case with typical assets. This is why there is a lot of warnings to users about this content.

Per one of our rendering specialists, Tom Hobson:

This was covered a number of times when that Open World Content and the Kite Demo Content released. What you’re seeing here is the DDC being written the first time a user clicks on this content. These are very High Poly assets with 8K textures. The first time they are clicked on in the content browser they will freeze the editor while this content is made into a readable state for UE4 (writing to the DDC). This is really exacerbated on lower-end machines and often lead to crashes when trying to load this content due to the way it was developed. This is why there is a warning with the content when you download it that it’s for extremely high-end machines.

“The assets in this pack are designed for extremely high-end systems. Load times of up to an hour are expected when opening the maps for the first time. Please also have 4GB of free space on your hard drive to accommodate the DerivedDataCache created by this content.”

So, besides the Speedtree assets, if are you finding this to be the case with typical, day to day assets (ie Static and Skeletal meshes, Blueprints, Materials & Textures etc.) and if you are comparing the same types of files you are able to move easily in Unity let us know how you are testing and we will continue to investigate this issue.



Alright, I will try and do some further testing.

i am using ue 4.18.3 on a resonable high spec machine
the kite demo is one instance of this bug but it is not the only instance. the same happens with the infinity blade levels as well. The copy, move, and save commands all seem to trigger a shader compile of all files during copy/move/save the ui becomess unresponsive and after a significant amount of time (sometime hours) the copy/move/save succeeds to recreate the save
create blank project
add infinity fire/ice/grass and kitedemo to project i dont think it matters what projects you add as long as they have lots of shaders
in project browser type map and set filter to level
right click each level and select save system will become unresponsive as you save more and more levels

Can’t you put the Redirectors in a single file in the root directory to reference where everything is? When you move something it will just have to change its location in that one folder? Even if a redirector contains a lot of info you could still contain that in one folder!

{ File: "File" Location: "Location!" Other info: " " }

I hate having empty folders all over the place, I make a lot of changes to my folders because of the type of project I have. It should be faster too.