This was discovered externally and reported on UDN here: https://udn.unrealengine.com/questions/563268/mac-editor-crash-when-disable-ambient-occlusion.html ...
UE4Editor crashes when creating static meshes. Event at startup time while it tries to create default object it crash sometimes. ...
attached video below if you are unsure of repro ...
If the persistent level is open and a user attempts to open a sublevel that contains a navmesh, the editor will freeze and then crash. Frequency: 3/3 Crashreporter: N/A ...
Switch between levels in the content browser caused a crash while loading the level. Project On Google Drive: [Link Removed] ...
Attempting to open a map through the content browser will crash the editor if that map is opened as a sublevel or the currently opened map through the world composition browser. Frequency: 2/2 Cr ...
Mousing over a softclasspath pin from a struct while debugging a Blueprint can lead to a crash. ...
BRANCH: MAIN CHANGELIST: 2322258 PLATFORM: Windows DESCRIPTION: When using a texture sample with the MipValueMode to MipLevel or MipBias with a value of 4 or higher will cause a crash. ...