The user is getting a consistent error which does not allow him to open projects in 4.8 and 4.9.
Five reports from user's machine produce identical callstacks: Bugg 66074:
[Link Removed]
Unable to reproduce locally. User cannot reproduce on Mac Tower or Similar Laptop.
UE4Editor-Slate.dylib!FTabManager::RestoreFrom(TSharedRef<FTabManager::FLayout, (ESPMode)0> const&, TSharedPtr<SWindow,()
UE4Editor-LevelEditor.dylib!SLevelEditor::RestoreContentArea(TSharedRef<SDockTab, (ESPMode)0> const&, TSharedRef<SWindow,()
UE4Editor-LevelEditor.dylib!SLevelEditor::Initialize(TSharedRef<SDockTab, (ESPMode)0> const&, TSharedRef<SWindow,()
UE4Editor-LevelEditor.dylib!FLevelEditorModule::SpawnLevelEditor()
UE4Editor-LevelEditor.dylib!TBaseRawMethodDelegateInstance<false, FLevelEditorModule, TSharedRef<SDockTab, (ESPMode)0> (FSpawnTabArgs const&)>::Execute()
UE4Editor-Slate.dylib!FTabManager::SpawnTab(FTabId const&, TSharedPtr<SWindow,()
UE4Editor-Slate.dylib!FTabManager::RestoreArea_Helper(TSharedRef<FTabManager::FLayoutNode, (ESPMode)0> const&, TSharedPtr<SWindow,()
UE4Editor-Slate.dylib!FTabManager::RestoreSplitterContent(TSharedRef<FTabManager::FSplitter, (ESPMode)0> const&, TSharedRef<SDockingSplitter, (ESPMode)0> const&, TSharedPtr<SWindow,()
UE4Editor-Slate.dylib!FTabManager::RestoreArea_Helper(TSharedRef<FTabManager::FLayoutNode, (ESPMode)0> const&, TSharedPtr<SWindow,()
UE4Editor-Slate.dylib!FTabManager::RestoreArea(TSharedRef<FTabManager::FArea, (ESPMode)0> const&, TSharedPtr<SWindow,()
UE4Editor-Slate.dylib!FTabManager::RestoreFrom(TSharedRef<FTabManager::FLayout, (ESPMode)0> const&, TSharedPtr<SWindow,()
UE4Editor-MainFrame.dylib!FMainFrameModule::CreateDefaultMainFrame()
UE4Editor-UnrealEd.dylib!EditorInit()
UE4Editor!GuardedMain()
UE4Editor!<Unknown>
Head over to the existing Questions & Answers thread and let us know what's up.