# Unreal Engine Crashing When Flattening **URL:** \ **Category:** Programming & Scripting\ **Tags:** unreal-engine\ **Created:** [May 5, 2024, 4:45pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518 "2024-05-05T16:45:55Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Goatlordish](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Goatlordish](https://forums.unrealengine.com/u/Goatlordish)\ **Post date:** [May 5, 2024, 4:45pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/1 "2024-05-05T16:45:55Z")
When I use the flatten tool on my landscape, the editor crashes. I am using unreal engine 5.4.1 on a Mac Mini M2. ---
**Author:** ![SpudMcKenzie](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/spudmckenzie/32/937130_2.png) [@SpudMcKenzie](https://forums.unrealengine.com/u/SpudMcKenzie)\ **Post date:** [May 5, 2024, 4:50pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/2 "2024-05-05T16:50:08Z")
When Unreal Engine crashes during the use of the landscape editing tools, such as the flatten tool, it typically points to a few potential issues such as graphics driver problems, memory limitations, or specific bugs in the Unreal Engine itself. Given that you’re using a Mac Mini M2 with Unreal Engine 5.4.1, here are some steps you can take to diagnose and possibly resolve the issue: ### 1. **Check Unreal Engine Version** Ensure that you are using the most up-to-date version of Unreal Engine. Sometimes, bugs that cause crashes are fixed in newer versions or patches. ### 2. **Update macOS** Ensure your operating system is updated. Apple frequently releases updates that improve hardware compatibility and performance, which can in turn help with software stability. ### 3. **Graphics and Hardware Considerations** - **Graphics API** : Unreal Engine on macOS uses Metal for rendering. Ensure that there are no known issues with Metal on the M2 chip in the context of Unreal Engine by checking forums or official Unreal Engine support channels. - **Memory Usage** : The Mac Mini M2, depending on your configuration, may have limited RAM, which can be a constraint when working with demanding tasks like landscape editing. Monitor your system’s memory usage to see if crashes correlate with high memory usage. ### 4. **Check for Error Logs** - After a crash, Unreal Engine usually generates a crash report. Look at the crash logs to identify any specific error messages or modules involved in the crash. You can find these logs in the Saved/Logs directory inside your project’s folder. ### 5. **Simplify Your Task** - If you’re working with a particularly complex or large landscape, try testing the flatten tool on a smaller or less complex part of the landscape to see if the issue persists. This can help determine if the problem is related to the complexity of the data. ### 6. **Test in a New Project** - Try replicating your landscape work in a new Unreal Engine project with similar settings. If the crash does not occur in the new project, there may be something specific in your original project causing the issue. ### 7. **Adjust Editor Settings** - **Reduce Editor Graphics Settings** : Lowering the graphics settings in Unreal Editor can sometimes help avoid crashes by reducing the load on the GPU and overall system resources. - **Landscape Tool Settings** : Adjust the tool settings, such as brush size and strength, to be less intensive to see if that avoids triggering a crash. Hope this helps. ---
**Author:** ![Goatlordish](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Goatlordish](https://forums.unrealengine.com/u/Goatlordish)\ **Post date:** [May 5, 2024, 6:02pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/3 "2024-05-05T18:02:43Z")
Thanks for the advice! After some testing I’ve found: 1. The crash occurs in other projects as well 2. It appears to be related to disk writing, here’s the error: Event: disk writes Action taken: none Writes: 2148.37 MB of file backed memory dirtied over 638 seconds (3368.90 KB per second average), exceeding limit of 24.86 KB per second over 86400 seconds Writes limit: 2147.48 MB Limit duration: 86400s Writes caused: 2148.37 MB Writes duration: 638s Duration: 637.71s Duration Sampled: 0.46s Steps: 28 (10.49 MB/step) Any ideas? I’ve tried making the brush size 1 but with the same results. ---
**Author:** ![motionlenn](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@motionlenn](https://forums.unrealengine.com/u/motionlenn)\ **Post date:** [May 6, 2024, 3:04pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/4 "2024-05-06T15:04:33Z")
I have the same issue. Unreal 5.4.1 with Macbook M3 Max. I found that some tools (like flatten and smooth) have a setting called “Combined layers operation”. Disabling this fixed the issue and is not resulting in an immediate crash. Same computer with Unreal Version 5.3 is not causing the issue. It is most likely a bug in version 5.4.1 ---
**Author:** ![Goatlordish](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Goatlordish](https://forums.unrealengine.com/u/Goatlordish)\ **Post date:** [May 6, 2024, 8:38pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/5 "2024-05-06T20:38:40Z")
Disabling Combined layers worked! Thank you so much! ---
**Author:** ![MoreTM](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/moretm/32/935256_2.png) [@MoreTM](https://forums.unrealengine.com/u/MoreTM)\ **Post date:** [May 9, 2024, 9:42am UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/6 "2024-05-09T09:42:02Z")
This solved the problem. Thank you! ---
**Author:** ![Jamestory-69](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Jamestory-69](https://forums.unrealengine.com/u/Jamestory-69)\ **Post date:** [June 5, 2024, 5:04pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/7 "2024-06-05T17:04:27Z")
For what its worth have the same problem on an M1 Ultra with 128GB of memory and having updated to 5.4.2 today. And thanks yes the Un-checking Combined layers fixed the problem. ---
**Author:** ![Alfreddiculous](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Alfreddiculous](https://forums.unrealengine.com/u/Alfreddiculous)\ **Post date:** [July 19, 2024, 2:22pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/8 "2024-07-19T14:22:16Z")
The issue seems to be fixed in 5.4.3. ---
**Author:** ![Elitic](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Elitic](https://forums.unrealengine.com/u/Elitic)\ **Post date:** [June 24, 2026, 7:43pm UTC](https://forums.unrealengine.com/t/unreal-engine-crashing-when-flattening/1841518/9 "2026-06-24T19:43:21Z")
UE 5.7.4 still crashing using flatten or smooth landscape tool. Unchecking “Combined Layers Operation” prevents crash but removes necessary functionality. `Assertion failed: EnumHasAllFlags(SupportedTargetTypeState.GetTargetTypeMask(), GetLandscapeToolTargetTypeAsFlags(InTargetType)) [File:D:\build++UE5\Sync\Engine\Source\Runtime\Landscape\Private\LandscapeEditLayerRendererState.cpp] [Line: 63]` `Target type ELandscapeToolTargetType::Heightmap cannot be enabled on this renderer state because it is not supported. Make sure that target types are supported before enabling them` 253x253 Landscape. Base Layer → Landmass Splines Layer → Splines Layer (roads) → Landmass Splines Layer → Final Layer.