I can verify this. Just noticed it. Closing SteamVR while the editor is running will automatically shut down the editor without warning or any prompt to save current work (found out thew hard way).
Unfortunately this is not an issue with the editor. It is a Steam VR issue, which is something that we are unable to fix. For assistance with the issue, please post on their forums.
How about when the editor receives a quit request it prompts a save dialog? It’s extremely frustrating to loose work because you forgot and closed steamvr while working on level editing in UE4. Still no fix from Valve.
(Personally I wish UE4 and visual studio would just save instantly whenever you make a change like jetbrains IDEs do. manually saving is so 5 years ago.)
Yeah I’m having the same issue and now I’m just manually unplugging the breakout box to swith off the HMD when not in use (not ideal but avoids the closing steamVR / UE4 issue). Also it doesn’t solve other people’s issues of sleeping lightboxes. Valve say they’ve already blacklisted UE4Editor.exe but it’s gone quiet since May so it seems as if nothing’s being done their end