[UE 5.8.3 HotFix Bug)

General Issues and Bug Reporting (Unreal Engine)
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Summary

[5.8.3] Abnormal RAM usage + UE freeze for more than a minute + fault report from the diagnostic service

What Type of Bug are you experiencing?

Foundation (C++ Tools, Profiling, & Pipeline)

Steps to Reproduce

Hello,
I have been developing on version 5.8.2 for a few months. I am currently creating a multiplayer game via Steam.
I was running tests just yesterday, and everything went smoothly when launching maps or the game.
Today, I updated to version 5.8.3.

  1. Since then, when I launch the game from Unreal in PIE/2-player/listen server mode, the game runs extremely sluggishly.
  2. I get a message stating that I do not have enough memory. I currently have 35 GB of DDR5 RAM. That is a decent amount; everything worked perfectly on version 5.8.2.
  3. It is evident that my memory is completely maxed out, whereas this was not the case before.
  4. When I exit the game, the entire Unreal editor freezes and becomes unresponsive. After waiting one or two minutes, I can interact with the software again, but the RAM remains maxed out. There is heavy data exchange with the SSD.
  5. It is impossible to continue working; the software has become unstable and frequently lags.
    Below are the diagnostics from the editor. I never encountered this issue with version 5.8.2.
    I have restarted the computer, but the problem recurs every time I launch the game within the editor.

Expected Result

Normal launch, smooth performance, game fully functional

Observed Result

memory is completely maxed

Affects Versions

5.8

Platform(s)

Windows

For crash reports, include your callstack

Engine Version: 5.8.3-58210709+++UE5+Release-5.8
Stall Detector: FEngineLoop::Tick
Stall Duration: 4.921725
Stall Time: 2026.09.22-18.52.22

StackTrace

00: [0x00007FFD47BB2A45] [UnrealEditor-Core.dll] : : <>:0
01: [0x00007FFD47BC8AD3] [UnrealEditor-Core.dll] : : <>:0
02: [0x00007FFD47BB3983] [UnrealEditor-Core.dll] : : <>:0
03: [0x00007FFD47B84343] [UnrealEditor-Core.dll] : : <>:0
04: [0x00007FFD47BA2757] [UnrealEditor-Core.dll] : : <>:0
05: [0x00007FFD4029F3CA] [UnrealEditor-SlateCore.dll] : : <>:0
06: [0x00007FFD40874A9B] [UnrealEditor-Slate.dll] : : <>:0
07: [0x00007FFD4086C73A] [UnrealEditor-Slate.dll] : : <>:0
08: [0x00007FFD40908805] [UnrealEditor-Slate.dll] : : <>:0
09: [0x00007FFD408F5ECC] [UnrealEditor-Slate.dll] : : <>:0
10: [0x00007FFD40A13C04] [UnrealEditor-Slate.dll] : : <>:0
11: [0x00007FFD40A121C8] [UnrealEditor-Slate.dll] : : <>:0
12: [0x00007FFD409B924F] [UnrealEditor-Slate.dll] : : <>:0
13: [0x00007FFD409EF8A6] [UnrealEditor-Slate.dll] : : <>:0
14: [0x00007FFD40A1E009] [UnrealEditor-Slate.dll] : : <>:0
15: [0x00007FFD228AEE90] [UnrealEditor-EditorPerformance.dll] : : <>:0
16: [0x00007FFD22892CC2] [UnrealEditor-EditorPerformance.dll] : : <>:0
17: [0x00007FFD40B369EB] [UnrealEditor-Slate.dll] : : <>:0
18: [0x00007FFD40B72A43] [UnrealEditor-Slate.dll] : : <>:0
19: [0x00007FFD40871A8A] [UnrealEditor-Slate.dll] : : <>:0
20: [0x00007FFD408BA75E] [UnrealEditor-Slate.dll] : : <>:0
21: [0x00007FFD408ACA1F] [UnrealEditor-Slate.dll] : : <>:0
22: [0x00007FFD408A453E] [UnrealEditor-Slate.dll] : : <>:0
23: [0x00007FFD40FD3323] [UnrealEditor-ApplicationCore.dll] : : <>:0
24: [0x00007FFD40FBE9EA] [UnrealEditor-ApplicationCore.dll] : : <>:0
25: [0x00007FFD40FD68E1] [UnrealEditor-ApplicationCore.dll] : : <>:0
26: [0x00007FFD40FBAC61] [UnrealEditor-ApplicationCore.dll] : : <>:0
27: [0x00007FFE545252C6] [USER32.dll] : : <>:0
28: [0x00007FFE54525D9D] [USER32.dll] : : <>:0
29: [0x00007FFD41007279] [UnrealEditor-ApplicationCore.dll] : : <>:0
30: [0x00007FF708542175] [UnrealEditor.exe] : : <>:0

Engine Version: 5.8.3-58210709+++UE5+Release-5.8
Stall Detector: FEngineLoop::Tick
Stall Duration: 349.512665
Stall Time: 2026.09.22-18.46.27

StackTrace

00: [0x00007FFE56444A14] [ntdll.dll] : : <>:0
01: [0x00007FFE56382ECB] [ntdll.dll] : : <>:0
02: [0x00007FFE5631941D] [ntdll.dll] : : <>:0
03: [0x00007FFD47A3FD5D] [UnrealEditor-Core.dll] : : <>:0
04: [0x00007FFD43D4EE79] [UnrealEditor-Engine.dll] : : <>:0
05: [0x00007FFD43D56DF5] [UnrealEditor-Engine.dll] : : <>:0
06: [0x00007FFD4661D40D] [UnrealEditor-CoreUObject.dll] : : <>:0
07: [0x00007FFD466640A6] [UnrealEditor-CoreUObject.dll] : : <>:0
08: [0x00007FFD46664501] [UnrealEditor-CoreUObject.dll] : : <>:0
09: [0x00007FFD465E8043] [UnrealEditor-CoreUObject.dll] : : <>:0
10: [0x00007FFD4666CA3A] [UnrealEditor-CoreUObject.dll] : : <>:0
11: [0x00007FFD46617D3B] [UnrealEditor-CoreUObject.dll] : : <>:0
12: [0x00007FFD3E6185D4] [UnrealEditor-UnrealEd.dll] : : <>:0
13: [0x00007FFD3DF9E00F] [UnrealEditor-UnrealEd.dll] : : <>:0
14: [0x00007FFD3EB07696] [UnrealEditor-UnrealEd.dll] : : <>:0
15: [0x00007FF708542779] [UnrealEditor.exe] : : <>:0
16: [0x00007FF70852C4AC] [UnrealEditor.exe] : : <>:0
17: [0x00007FF70852C5BA] [UnrealEditor.exe] : : <>:0
18: [0x00007FF708531256] [UnrealEditor.exe] : : <>:0
19: [0x00007FF708545C74] [UnrealEditor.exe] : : <>:0
20: [0x00007FF70854902A] [UnrealEditor.exe] : : <>:0
21: [0x00007FFE5435CD87] [KERNEL32.DLL] : : <>:0

2 
Hello,
I would like to confirm and add some details to what I said earlier:
As long as I am in the editor, everything works "normally."
When I run tests in PIE/2-player/listen server mode, things go fine on the first map (the main menu).
When the host starts the game and loads the new map, everything is okay; RAM usage increases slightly, but within very reasonable limits.
The spike in memory consumption occurs the moment the client player joins the ongoing game (Steam session). That is when things escalate: RAM usage climbs steadily for no apparent reason—increasing by about 100 MB per second. It becomes impossible to even exit the game properly (using the in-game function); everything freezes. Memory usage keeps rising until it hits the limit. The system slows to a crawl and stops responding, eventually resulting in an error message from UE as part of the diagnostic process.
I use translator from french