UnrealEngine5でマップを保存しようとするとクラッシュする、プロジェクトがひらけない

前提

2TB外付けHDD(東芝)にUEを入れて使用しています。ランチャーのみCです。

UE5.0.3にてマップを保存しようとするとアプリがクラッシュします。
また、その時に作られたデフォルトプロジェクトや、外部からダウンロードしたプロジェクトも一切ひらけません。

仕方なくUE4.27で作業していますが、こちらは基本的に同じ設定で何一つ問題なく動作しています。

よろしくお願いいたします。

実現したいこと

エラーの解決

発生している問題・エラーメッセージ

クラッシュした時とプロジェクトを開こうとした時の2つがあります

クラッシュした時

LoginId:---
EpicAccountId:---
Fatal error: [File:/Users/build/Build/++UE5/Sync/Engine/Source/Runtime/CoreUObject/Private/Misc/PackageName.cpp] [Line: 799] LongPackageNameToFilename failed to convert '/Volumes/TOSHIBA_EXT/Epic_Games/MyProject/Content/NewMap'. Path does not map to any roots.

FPackageName::LongPackageNameToFilename(FString const&, FString const&) Address = 0x10fc18fff (filename not found) [in UnrealEditor-CoreUObject.dylib]
SaveAsImplementation(UWorld*, FString const&, bool, FString*) Address = 0x1249822b2 (filename not found) [in UnrealEditor-UnrealEd.dylib]
FEditorFileUtils::SaveLevel(ULevel*, FString const&, FString*) Address = 0x12499b98b (filename not found) [in UnrealEditor-UnrealEd.dylib]
FEditorFileUtils::SaveCurrentLevel() Address = 0x12499d6b4 (filename not found) [in UnrealEditor-UnrealEd.dylib]
TBaseStaticDelegateInstance<void (), FDefaultDelegateUserPolicy>::ExecuteIfSafe() const Address = 0x1352c1667 (filename not found) [in UnrealEditor-LevelEditor.dylib]
FUICommandList::ConditionalProcessCommandBindings(FKey, bool, bool, bool, bool, bool) const Address = 0x114089de1 (filename not found) [in UnrealEditor-Slate.dylib]
FUICommandList::ProcessCommandBindings(FKeyEvent const&) const Address = 0x1140897f6 (filename not found) [in UnrealEditor-Slate.dylib]
SEditorViewport::OnKeyDown(FGeometry const&, FKeyEvent const&) Address = 0x124de8774 (filename not found) [in UnrealEditor-UnrealEd.dylib]
SLevelViewport::OnKeyDown(FGeometry const&, FKeyEvent const&) Address = 0x1353986a1 (filename not found) [in UnrealEditor-LevelEditor.dylib]
FSlateApplication::ProcessKeyDownEvent(FKeyEvent const&) Address = 0x11400063b (filename not found) [in UnrealEditor-Slate.dylib]
FSlateApplication::OnKeyDown(int, unsigned int, bool) Address = 0x113fff61c (filename not found) [in UnrealEditor-Slate.dylib]
FMacApplication::ProcessKeyDownEvent(FDeferredMacEvent const&, TSharedPtr<FMacWindow, (ESPMode)1>) Address = 0x10f27a35b (filename not found) [in UnrealEditor-ApplicationCore.dylib]
FMacApplication::ProcessEvent(FDeferredMacEvent const&) Address = 0x10f274435 (filename not found) [in UnrealEditor-ApplicationCore.dylib]
FMacApplication::ProcessDeferredEvents(float) Address = 0x10f27407f (filename not found) [in UnrealEditor-ApplicationCore.dylib]
FSlateApplication::TickPlatform(float) Address = 0x113fde9c7 (filename not found) [in UnrealEditor-Slate.dylib]
FSlateApplication::Tick(ESlateTickType) Address = 0x113fddf15 (filename not found) [in UnrealEditor-Slate.dylib]
FEngineLoop::Tick() Address = 0x10e95ebba (filename not found) [in UnrealEditor]
GuardedMain(char16_t const*) Address = 0x10e96b992 (filename not found) [in UnrealEditor]
-[UEAppDelegate runGameThread:] Address = 0x10e987033 (filename not found) [in UnrealEditor]
-[FCocoaGameThread main] Address = 0x111c98561 (filename not found) [in UnrealEditor-Core.dylib]
Unknown() Address = 0x7ff813524994 (filename not found) [in Foundation]
_pthread_start Address = 0x7ff8126094e1 (filename not found) [in libsystem_pthread.dylib]
thread_start Address = 0x7ff812604f6b (filename not found) [in libsystem_pthread.dylib]