Bee_backend hangs indefinitely after successful script compilation on Ubuntu (Unity 2021.3.45f2)

I’m running Unity 2021.3.45f2 on Ubuntu 24.04, working with a large project (many third-party asset packages: GPUInstancer, Procedural Worlds GTS/Flora, StylizedWater2, MeshBaker, etc.).

When opening a project, script compilation appears to complete successfully the log shows AssetDatabase: script compilation and the VBCSCompiler.dll (Roslyn compiler server) process exits cleanly but bee_backend never returns control to the Editor. It sits at 0% CPU indefinitely with zero child processes, and Unity appears frozen/hung, even though the actual compile work is done.

What I’ve confirmed:

  • Verified via ps/top that bee_backend truly has 0% CPU and no children after the compiler process exits it’s not silently working, it’s stalled.
  • The pattern repeats across multiple compile passes (including the automatic second pass Unity triggers after “Exiting safe mode”).
  • Manually kill -9-ing the stuck bee_backend process and letting Unity spawn a fresh one immediately unblocks progress each time, suggesting a broken handoff/IPC issue rather than an actual compile failure.
  • Ruled out: broken system dotnet installs, missing ICU libraries, inotify watch limits, and Library corruption (tested with a fresh empty project, which compiles fine).

This looks like a named-pipe IPC issue between bee_backend and the Roslyn shared compiler server (VBCSCompiler) on Linux, where the “compilation finished” signal isn’t reliably delivered back.

  1. Has anyone else hit this specific “compile succeeds but bee_backend hangs after” pattern on Linux?
  2. Is disabling the shared compiler server (via /shared-compilation- in csc.rsp) a known/recommended workaround for this, or is there a more targeted fix?
  3. Is this a known bug tracked on Unity’s issue tracker already?

what version of the unity hub are you on? just a guess as I’m on Windows but I’m experiencing a similar issue. could be related to this… after I updated I could no longer open my project. looks like others are experiencing similar issues Now Available: Unity Hub 3.19.5 - #6 by Rystall. I have rolled the hub back and so far things appear to be working