Very slow load times of UnrealEditor on new PC.

Development Platform & Builds
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Hi,

This is a left field question that someone might have run into before.

Brand new Alienware PC with specs of:

Intel i9-285K

RTX 5090

64gb RAM (Dual channel 6400 mt/s)

2x 4TB NVMe (Gen4)

The issue is when loading UE5 from a Perforce sync. The load of UE5 can take up to 5mins from a fresh boot, subsequent boots will be fast. After looking at captures from ProcMon (not an expert) everything is loading OK just takes a long time. Even when first double clicking on the icon it can take 30secs for loading dialog box to appear. Really hangs bad at ~70% mark for our project when loading all the DLL’s.

Now if I run UE5 the second time everything loads in about 20secs which is same as other machines I have (probably because files have been cached). For other PC’s we have from fresh boot of the PC UE5 will load in about 25secs.

Now if I install UE5 from Epic Games Launchers that loads really fast like it should. Installed number of games they all load fast.

Spent a few days trying to track down what it could be, unintsalling things. Even ended up re-installing Windows to see if that would fix it, but no. Turning off Windows Defender, turning off Firewall.

If its an idea I’ve tried it.

What issues could a built version of UE5 be doing???

Now the weird thing I did find this morning is by having no network (WiFi off, no LAN cable attached) it does load faster, nearer what it should be.

So what could be doing that???

First PC I have experienced this issue on.

If anyone has ideas I would love to hear if anyone has run into issue like this before or any ideas,

Thanks,

Simon

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Hello!

The long loading time for the first run would be related to the local DDC being generated. https://dev.epicgames.com/documentation/en\-us/unreal\-engine/using\-derived\-data\-cache\-in\-unreal\-engine

The TLDR is that the uasset files of the project contain the source version of the data (PNG, BMP, FBX…) and that the runtime version must be generated from that source data using the asset settings (compressed texture, Nanite clusters, compiled shaders…)

It is possible to set a Shared cache for the studio so that the data can be downloaded instead of being generated. There is the old Shared cache that is based on a network share and the new Zen shared cache. https://dev.epicgames.com/documentation/en\-us/unreal\-engine/set\-up\-zen\-storage\-server\-as\-shared\-ddc\-for\-unreal\-engine

For people working from home, the Zen Shared cache will offer better performance than the file share as network file access are usually slow under a VPN connection.

There is also a Cloud DDC (see initial doc link) that can be used to serve data to the users that are not connected to the office network.

Regarding the Launcher build of the Editor, it ships with a compressed cache that contains the engine\editor data in a ready to use state.

Regards,

Martin

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Since you mentioned this is on a brand new PC: We have run into similar issues before and tracked them down to a Windows feature called “Smart App Control” which is enabled by default on new Windows 11 installations.

This adds significant overhead to the loading of each DLL file, which can add up to a lot of time due to the number of DLLs loaded by the editor.

Disabling this feature in the Windows settings (Windows Security Settings → App and Browser Control → Smart App Control → Smart App Control Settings) solved the problem for us.

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Hi Martin & David,

David,

Disabling this feature in the Windows settings (Windows Security Settings → App and Browser Control → Smart App Control → Smart App Control Settings) solved the problem for us.

That was it!

Thank you so much,

Good thing to know for future, not sure how you found that nugget.

Now have to put PC back to how it was.

Martin good info to pass along.

And of course thank you Microsoft.

Best,

Simon

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