Project suddenly does not load

I’ve ben working on my UE project for several weeks now. Regularly saving all the content. Suddenly when I go to load the project up I get this window …

“The following drive locations have limited free space. It is recommended that you free some space to avoid issues such as crashed and data loss due to files not being able to be written and saved. 1,337 MB Free C:/Users/Owner/AppData/Local/UnrealEngine/4.26/The project directory.”

Followed by this message when I try to open the project …
“The following modules are missing or built with a different engine version: MyProject3 Would you like to rebuild them now?”

Rebuilding results in this message …
“MyProject3 could not be compiled. Try rebuilding from source manually.”

  • My project directory was set to another drive (D:\Epic Games\Unreal Projects) & this path still shows in the project icon in the launcher. Has the game accidently-reset the project folder?
  • I have VS2019 installed & up to date.
  • Log file below …
  • [SPOILER]
  • Log file open, 01/23/21 16:00:00
    LogInit: LLM is enabled
    LogInit: LLM CsvWriter: off TraceWriter: off
    LogInit: Display: Running engine for game: MyProject3
    LogPlatformFile: Not using cached read wrapper
    LogTaskGraph: Started task graph with 5 named threads and 23 total threads with 3 sets of task threads.
    LogStats: Stats thread started at 0.206702
    LogD3D11RHI: Loaded GFSDK_Aftermath_Lib.x64.dll
    LogICUInternationalization: ICU TimeZone Detection - Raw Offset: +10:00, Platform Override: ‘’
    LogPluginManager: Mounting plugin MeshPainting
    LogPluginManager: Mounting plugin XGEController
    LogPluginManager: Mounting plugin Paper2D
    LogPluginManager: Mounting plugin AISupport
    LogPluginManager: Mounting plugin EnvironmentQueryEditor
    LogPluginManager: Mounting plugin LightPropagationVolume
    LogPluginManager: Mounting plugin CameraShakePreviewer
    LogPluginManager: Mounting plugin AnimationSharing
    LogPluginManager: Mounting plugin CLionSourceCodeAccess
    LogPluginManager: Mounting plugin AssetManagerEditor
    LogPluginManager: Mounting plugin CryptoKeys
    LogPluginManager: Mounting plugin CurveEditorTools
    LogPluginManager: Mounting plugin DataValidation
    LogPluginManager: Mounting plugin CodeLiteSourceCodeAccess
    LogPluginManager: Mounting plugin FacialAnimation
    LogPluginManager: Mounting plugin GameplayTagsEditor
    LogPluginManager: Mounting plugin GeometryMode
    LogPluginManager: Mounting plugin MacGraphicsSwitching
    LogPluginManager: Mounting plugin MaterialAnalyzer
    LogPluginManager: Mounting plugin GitSourceControl
    LogPluginManager: Mounting plugin MobileLauncherProfileWizard
    LogPluginManager: Mounting plugin KDevelopSourceCodeAccess
    LogPluginManager: Mounting plugin PluginBrowser
    LogPluginManager: Mounting plugin NullSourceCodeAccess
    LogPluginManager: Mounting plugin SpeedTreeImporter
    LogPluginManager: Mounting plugin PlasticSourceControl
    LogPluginManager: Mounting plugin PerforceSourceControl
    LogPluginManager: Mounting plugin PluginUtils
    LogPluginManager: Mounting plugin PropertyAccessNode
    LogPluginManager: Mounting plugin RiderSourceCodeAccess
    LogPluginManager: Mounting plugin SubversionSourceControl
    LogPluginManager: Mounting plugin UObjectPlugin
    LogPluginManager: Mounting plugin Niagara
    LogPluginManager: Mounting plugin VisualStudioCodeSourceCodeAccess
    LogPluginManager: Mounting plugin VisualStudioSourceCodeAccess
    LogPluginManager: Mounting plugin XCodeSourceCodeAccess
    LogPluginManager: Mounting plugin AlembicImporter
    LogPluginManager: Mounting plugin AutomationUtils
    LogPluginManager: Mounting plugin BackChannel
    LogPluginManager: Mounting plugin ChaosClothEditor
    LogPluginManager: Mounting plugin ChaosCloth
    LogPluginManager: Mounting plugin ChaosEditor
    LogPluginManager: Mounting plugin ChaosSolverPlugin
    LogPluginManager: Mounting plugin CharacterAI
    LogPluginManager: Mounting plugin ChaosNiagara
    LogPluginManager: Mounting plugin EasyBallistics
    LogPluginManager: Mounting plugin LuminPlatformFeatures
    LogPluginManager: Mounting plugin MagicLeap
    LogPluginManager: Mounting plugin MagicLeapLightEstimation
    LogPluginManager: Mounting plugin MagicLeapMedia
    LogPluginManager: Mounting plugin GeometryCache
    LogPluginManager: Mounting plugin GeometryCollectionPlugin
    LogPluginManager: Mounting plugin MagicLeapPassableWorld
    LogPluginManager: Mounting plugin GeometryProcessing
    LogPluginManager: Mounting plugin DatasmithContent
    LogPluginManager: Mounting plugin MLSDK
    LogPluginManager: Mounting plugin VariantManagerContent
    LogPluginManager: Mounting plugin AndroidMedia
    LogPluginManager: Mounting plugin AvfMedia
    LogPluginManager: Mounting plugin ImgMedia
    LogPluginManager: Mounting plugin MediaCompositing
    LogPluginManager: Mounting plugin MediaPlayerEditor
    LogPluginManager: Mounting plugin MotoSynth
    LogPluginManager: Mounting plugin TcpMessaging
    LogPluginManager: Mounting plugin WmfMedia
    LogPluginManager: Mounting plugin PlanarCut
    LogPluginManager: Mounting plugin UdpMessaging
    LogPluginManager: Mounting plugin ProxyLODPlugin
    LogPluginManager: Mounting plugin WebMMedia
    LogPluginManager: Mounting plugin PlatformCrypto
    LogPluginManager: Mounting plugin RawInput
    LogPluginManager: Mounting plugin SkeletalReduction
    LogPluginManager: Mounting plugin ActorSequence
    LogPluginManager: Mounting plugin LevelSequenceEditor
    LogPluginManager: Mounting plugin MatineeToLevelSequence
    LogPluginManager: Mounting plugin TemplateSequence
    LogPluginManager: Mounting plugin OnlineSubsystem
    LogPluginManager: Mounting plugin OnlineSubsystemNull
    LogPluginManager: Mounting plugin LauncherChunkInstaller
    LogPluginManager: Mounting plugin OnlineSubsystemUtils
    LogPluginManager: Mounting plugin ActorLayerUtilities
    LogPluginManager: Mounting plugin AndroidDeviceProfileSelector
    LogPluginManager: Mounting plugin AndroidMoviePlayer
    LogPluginManager: Mounting plugin ApexDestruction
    LogPluginManager: Mounting plugin AndroidPermission
    LogPluginManager: Mounting plugin AppleMoviePlayer
    LogPluginManager: Mounting plugin AppleImageUtils
    LogPluginManager: Mounting plugin ArchVisCharacter
    LogPluginManager: Mounting plugin AssetTags
    LogPluginManager: Mounting plugin AudioCapture
    LogPluginManager: Mounting plugin AudioSynesthesia
    LogPluginManager: Mounting plugin CableComponent
    LogPluginManager: Mounting plugin ChunkDownloader
    LogPluginManager: Mounting plugin CustomMeshComponent
    LogPluginManager: Mounting plugin EditableMesh
    LogPluginManager: Mounting plugin ExampleDeviceProfileSelector
    LogPluginManager: Mounting plugin ScreenshotTools
    LogPluginManager: Mounting plugin GoogleCloudMessaging
    LogPluginManager: Mounting plugin GooglePAD
    LogPluginManager: Mounting plugin IOSDeviceProfileSelector
    LogPluginManager: Mounting plugin LinuxDeviceProfileSelector
    LogPluginManager: Mounting plugin LocationServicesBPLibrary
    LogPluginManager: Mounting plugin MobilePatchingUtils
    LogPluginManager: Mounting plugin PostSplashScreen
    LogPluginManager: Mounting plugin PhysXVehicles
    LogPluginManager: Mounting plugin ProceduralMeshComponent
    LogPluginManager: Mounting plugin RuntimePhysXCooking
    LogPluginManager: Mounting plugin SignificanceManager
    LogPluginManager: Mounting plugin SoundFields
    LogPluginManager: Mounting plugin SunPosition
    LogPluginManager: Mounting plugin Synthesis
    LogPluginManager: Mounting plugin WebMMoviePlayer
    LogPluginManager: Mounting plugin PropertyAccessEditor
    LogPluginManager: Mounting plugin WindowsMoviePlayer
    LogPluginManager: Mounting plugin ContentBrowserAssetDataSource
    LogPluginManager: Mounting plugin ContentBrowserClassDataSource
    LogPluginManager: Mounting plugin OnlineSubsystemIOS
    LogPluginManager: Mounting plugin OnlineSubsystemGooglePlay
    LogPluginManager: Mounting plugin OculusVR
    LogPluginManager: Mounting plugin SteamVR
    LogXGEController: Cannot use XGE Controller as Incredibuild is not installed on this machine.
    LogInit: Warning: Incompatible or missing module: MyProject3
    Running D:/Epic Games/UE_4.26/Engine/Binaries/DotNET/UnrealBuildTool.exe Development Win64 -Project=“D:/Epic Games/Unreal Projects/MyProject3/MyProject3.uproject” -TargetType=Editor -Progress -NoEngineChanges -NoHotReloadFromIDE
    WARNING: Visual Studio 2019 is installed, but is missing the C++ toolchain. Please verify that the “VC++ 2019 toolset” component is selected in the Visual Studio 2019 installation options.
    ERROR: Visual Studio 2019 must be installed in order to build this target.
    LogInit: Warning: Still incompatible or missing module: MyProject3
    LogCore: Engine exit requested (reason: EngineExit() was called)
    LogExit: Preparing to exit.
    LogModuleManager: Shutting down and abandoning module DesktopPlatform (48)
    LogModuleManager: Shutting down and abandoning module PlatformCryptoOpenSSL (46)
    LogModuleManager: Shutting down and abandoning module PlatformCryptoTypes (44)
    LogModuleManager: Shutting down and abandoning module PlatformCrypto (42)
    LogModuleManager: Shutting down and abandoning module XGEController (40)
    LogModuleManager: Shutting down and abandoning module AnimationModifiers (38)
    LogModuleManager: Shutting down and abandoning module AudioEditor (36)
    LogModuleManager: Shutting down and abandoning module PropertyEditor (35)
    LogModuleManager: Shutting down and abandoning module TextureCompressor (32)
    LogModuleManager: Shutting down and abandoning module RenderCore (30)
    LogModuleManager: Shutting down and abandoning module Landscape (28)
    LogModuleManager: Shutting down and abandoning module SlateRHIRenderer (26)
    LogModuleManager: Shutting down and abandoning module OpenGLDrv (24)
    LogModuleManager: Shutting down and abandoning module D3D11RHI (22)
    LogModuleManager: Shutting down and abandoning module AnimGraphRuntime (20)
    LogModuleManager: Shutting down and abandoning module Renderer (18)
    LogModuleManager: Shutting down and abandoning module Engine (16)
    LogModuleManager: Shutting down and abandoning module CoreUObject (14)
    LogModuleManager: Shutting down and abandoning module NetworkFile (12)
    LogModuleManager: Shutting down and abandoning module CookedIterativeFile (10)
    LogModuleManager: Shutting down and abandoning module StreamingFile (8)
    LogModuleManager: Shutting down and abandoning module SandboxFile (6)
    LogModuleManager: Shutting down and abandoning module PakFile (4)
    LogModuleManager: Shutting down and abandoning module RSA (3)
    LogExit: Exiting.
    Log file closed, 01/23/21 16:00:06
  • [/SPOILER]

Sounds like you’re running low on drive space for where your engine is installed, not necessarily the project. Unreal is a memory hog, engine and projects. I like to keep both on a separate harddrive from the OS.

The AppData folder is a mystery to me. Not sure how you could handle that if it’s normally storing on your C. Moving the engine and projects to another drive should free up plenty of space though. Be sure to verify the engine after you’ve moved it or else you’ll need to reinstall the engine cleanly onto another drive.

The launcher still thinks your project is in the original location. This information lives in the DerivedDataCache, Saved, and Intermediate folders of your project. You can delete them and then try launching it again - use the uproject file for good measure.

There might be other factors that I’m not aware of so take this as general advice. Don’t do anything that you feel will remove your hard work. Backup if anything and take the time to consider what will happen before doing. Good luck!