I am using macOS Mojave (10.14.6) and XCode 11. However, I keep getting this error when I launch unreal and it ALWAYS crashes on 10% and occasionally 18%. It ran once fine but now it keeps crashing. Here is the logs, help please!
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Assertion failed: SerializeNum >= 0 [File:/Users/build/Build/++UE4/Sync/Engine/Source/Runtime/Core/Public/Containers/Array.h] [Line: 1152]
FGenericPlatformMisc::RaiseException(unsigned int) Address = 0x10b8d8d67 (filename not found) [in UE4Editor-Core.dylib]
FMacErrorOutputDevice::Serialize(char16_t const*, ELogVerbosity::Type, FName const&) Address = 0x10ba70033 (filename not found) [in UE4Editor-Core.dylib]
FOutputDevice::LogfImpl(char16_t const*, ...) Address = 0x10bb54e79 (filename not found) [in UE4Editor-Core.dylib]
AssertFailedImplV(char const*, char const*, int, char16_t const*, __va_list_tag*) Address = 0x10bad4e5e (filename not found) [in UE4Editor-Core.dylib]
FDebug::CheckVerifyFailedImpl(char const*, char const*, int, char16_t const*, ...) Address = 0x10bad4cf4 (filename not found) [in UE4Editor-Core.dylib]
operator<<(FArchive&, TArray >&) Address = 0x12908607d (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FMemoryDerivedDataBackend::LoadCache(char16_t const*) Address = 0x1290864f4 (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseBootCache(char16_t const*, char16_t const*, FString&) Address = 0x129091a75 (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseNode(char16_t const*, FString const&, char16_t const*, TMap >&) Address = 0x12908eab7 (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseHierarchicalCache(char16_t const*, char16_t const*, FString const&, char16_t const*, TMap >&) Address = 0x129091e4b (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseNode(char16_t const*, FString const&, char16_t const*, TMap >&) Address = 0x12908ea9c (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseAsyncPut(char16_t const*, char16_t const*, FString const&, char16_t const*, TMap >&) Address = 0x129092589 (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseNode(char16_t const*, FString const&, char16_t const*, TMap >&) Address = 0x12908ec2c (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseKeyLength(char16_t const*, char16_t const*, FString const&, char16_t const*, TMap >&) Address = 0x12909219b (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::ParseNode(char16_t const*, FString const&, char16_t const*, TMap >&) Address = 0x12908ebf1 (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataBackendGraph::FDerivedDataBackendGraph() Address = 0x12908debe (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataCache::FDerivedDataCache() Address = 0x1290a0310 (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FDerivedDataCacheModule::GetDDC() Address = 0x1290a014a (filename not found) [in UE4Editor-DerivedDataCache.dylib]
FModuleManager::LoadModuleWithFailureReason(FName, EModuleLoadResult&) Address = 0x10bbb66dc (filename not found) [in UE4Editor-Core.dylib]
FModuleManager::LoadModule(FName) Address = 0x10bbb5799 (filename not found) [in UE4Editor-Core.dylib]
GetDerivedDataCache() Address = 0x10bb2b11f (filename not found) [in UE4Editor-Core.dylib]
GetDerivedDataCacheRef() Address = 0x10bb2b15b (filename not found) [in UE4Editor-Core.dylib]
CompileGlobalShaderMap(EShaderPlatform, ITargetPlatform const*, bool) Address = 0x10dc940fe (filename not found) [in UE4Editor-Engine.dylib]
FEngineLoop::PreInitPreStartupScreen(char16_t const*) Address = 0x10a5bc5f1 (filename not found) [in UE4Editor]
GuardedMain(char16_t const*) Address = 0x10a5b24ed (filename not found) [in UE4Editor]
-[UE4AppDelegate runGameThread:] Address = 0x10a5cf07f (filename not found) [in UE4Editor]
-[FCocoaGameThread main] Address = 0x10ba42931 (filename not found) [in UE4Editor-Core.dylib]
Unknown() Address = 0x7fff402ef0c2 (filename not found) [in Foundation]
_pthread_body Address = 0x7fff6a2562eb (filename not found) [in libsystem_pthread.dylib]
_pthread_start Address = 0x7fff6a259249 (filename not found) [in libsystem_pthread.dylib]
thread_start Address = 0x7fff6a25540d (filename not found) [in libsystem_pthread.dylib]