[CrashReport] Crash related to lack of disk space - FShaderCompileThreadRunnable::WriteNewTasks()

• Sent in the unattended mode
• 4.9- In this crash I was trying to do a LOD only build. Originally it was a full build but after four crashes that way I clicked just LOD to see if it would work on its? own and still crashed so I assume the issue to be in the hierarchical LOD. It is a large area that I am running for tests so I think I will see if I can do smaller portions at a time. I?m not sure how far along it was before the crash but at least more than half way since the last I looked it was in the Ms. I
• I tried to open a project which I converted from 4.8 to 4.9
• something about landscape?

Unable to reproduce internally, but appears related to users storing their projects in shared cloud storage folders. All Error Messages seem to indicate projects in Drive or Dropbox folders.

Update by Eric.K: "after a little more digging into each reported version of this crash. It appears this has something to do with Dropbox, Google Drive or OneDrive syncing the project directory and some file is not correctly allowed to update in the Intermediate Folder while compiling a Material or other element. I am attempting to reach out to someone who had this issue and get a project that I can try to sync to a dropbox and reproduce."

I reproduced crashes by using ShaderWorkingDir= to remap the source temp files to the destination drive, and then filled up all the space.

UE4Editor_Engine!FShaderCompileThreadRunnable::WriteNewTasks() [shadercompiler.cpp:552]
UE4Editor_Engine!FShaderCompileThreadRunnable::CompilingLoop() [shadercompiler.cpp:753]
UE4Editor_Engine!FShaderCompileThreadRunnableBase::Run() [shadercompiler.cpp:357]
UE4Editor_Core!FRunnableThreadWin::Run() [windowsrunnablethread.cpp:74]