After restarting my computer, I tried to reload a previously loaded model in LM Studio, but it failed with an error.

[zouchengli]

Which version of LM Studio?
Version 0.4.7+4 (0.4.7+4)

Which operating system?
macOS 26.3.1 (Apple Silicon)

What is the bug?
After restarting my computer, I tried to reload a previously loaded model in LM Studio, but it failed with an error. The error indicates that the libpython3.11.dylib library is missing, causing the MLX backend engine to fail during initialization. It appears that the Python dynamic library path is incorrect when the backend tries to load.

Screenshots

Logs

Failed to load last used model.
Failed to load LLM engine from path: /Users/chengli.zou/.lmstudio/extensions/backends/mlx-llm-mac-arm64-apple-metal-advsimd-1.3.0/llm_engine_mlx_amphibian.node. dlopen(/Users/chengli.zou/.lmstudio/extensions/backends/mlx-llm-mac-arm64-apple-metal-advsimd-1.3.0/llm_engine_mlx_amphibian.node, 0x0001): Library not loaded: @rpath/libpython3.11.dylib
  Referenced from: <E870D7A6-E508-351B-957C-8FF18CE3932B> /Users/chengli.zou/.lmstudio/extensions/backends/mlx-llm-mac-arm64-apple-metal-advsimd-1.3.0/libllm_engine.dylib
  Reason: tried: '/Users/chengli.zou/.lmstudio/extensions/backends/vendor/_amphibian/cpython3.11-mac-arm64@10/lib/libpython3.11.dylib' (no such file), '/Users/chengli.zou/.lmstudio/extensions/backends/mlx-llm-mac-arm64-apple-metal-advsimd-1.3.0/libpython3.11.dylib' (no such file), '/Users/chengli.zou/.lmstudio/extensions/backends/mlx-llm-mac-arm64-apple-metal-advsimd-1.3.0/libpython3.11.dylib' (no such file), '/Users/chengli.zou/.lmstudio/extensions/backends/mlx-llm-mac-arm64-apple-metal-advsimd-1.3.0/libpython3.11.dylib' (no such file)

To Reproduce
Steps to reproduce the behavior:

1. install LM Studio 0.4.7+4 and load a model using the MLX backend
2. Use the model normally, then restart your computer
3. Open LM Studio again and try to reload the previously used model
4. The model fails to load with the error shown above

[yrahul3910]

I've sporadically run into this, though I can't tell what the minimum requirement to trigger this is. Sometimes just closing and reopening the app triggered it for me, for example. What's interesting is that uninstalling the app (without deleting ~/.lmstudio) and then reinstalling it works fine.

Depending on how you installed Python on your machine, this might be slightly different, but in theory just symlinking the libpython* should work (even if not the right version technically) as a workaround.

• If you used brew, then run fd -u /opt libpython (or if you don't have fd, then find /opt -name "*libpython*".
• If you used pyenv, then follow the instructions in this SO answer.

In either case, you should have a path to a libpython<version>.dylib, and in theory something like

ln -s <the path you found> /Users/chengli.zou/.lmstudio/extensions/backends/vendor/_amphibian/cpython3.11-mac-arm64@10/lib/libpython3.11.dylib

should suffice. For the second argument, I just picked one of the paths from the tried: line in the error.