Can't load Devstral 2 MLX

[taoeffect]

Which version of LM Studio?

LM Studio 0.3.34 (Build 1)

Which operating system?

macOS

What is the bug?

Can't load mlx-community/devstral-small-2-24b-instruct-2512 MLX.

Screenshots

Logs

[2025-12-09 11:07:16.604] [error] [LMSInternal][Client=LM Studio][Endpoint=loadModel] Error in channel handler: Error: Received load-error
    at _0x261035.<computed> (/Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:1193:145124)
    at _0x45d2f7._0xf678ad (/Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:121:6520)
    at _0x45d2f7.emit (node:events:519:28)
    at _0x45d2f7.onChildMessage (/Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:104:214345)
    at _0x45d2f7.onChildMessage (/Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:121:3994)
    at _0x392272.<anonymous> (/Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:104:213283)
    at _0x392272.emit (node:events:519:28)
    at ForkUtilityProcess.<anonymous> (/Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:664:17617)
    at ForkUtilityProcess.emit (node:events:519:28)
    at ForkUtilityProcess.a.emit (node:electron/js2c/browser_init:2:75042)
- Caused By: Error: Failed to load model
    at _0x2cbd4e.<computed>.load (/Applications/LM Studio.app/Contents/Resources/app/.webpack/lib/llmworker.js:85:15673)
    at async _0x205d44.loadModel (/Applications/LM Studio.app/Contents/Resources/app/.webpack/lib/llmworker.js:121:14725)
    at async _0x205d44.handleMessage (/Applications/LM Studio.app/Contents/Resources/app/.webpack/lib/llmworker.js:121:6257)
[2025-12-09 11:07:16.604] [error] [LMSInternal][Client=LM Studio][Endpoint=loadModel] No instance reference assigned before error
[2025-12-09 11:07:16.901] [error] [LMSInternal][Client=LM Studio][Endpoint=countTokens] Error in RPC handler: Error: Model is unloaded.
    at /Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:121:3637
[2025-12-09 11:07:16.901] [error] Unhandled Rejection at: {} reason: Error: Model is unloaded.
    at /Applications/LM Studio.app/Contents/Resources/app/.webpack/main/index.js:121:3637

[bgeesaman]

I also get that same error in LM Studio 0.3.34, but also:

❯ mlx_lm.generate --model mlx-community/Devstral-Small-2-24B-Instruct-2512-4bit --max-tokens 16384 --temp 0.4 --prompt "Which languages do you understand and can explore confidently?"
...snip...
Traceback (most recent call last):
...snip...
devstral2-test/.venv/lib/python3.13/site-packages/transformers/tokenization_utils_base.py", line 1210, in _set_model_specific_special_tokens
    self.SPECIAL_TOKENS_ATTRIBUTES = self.SPECIAL_TOKENS_ATTRIBUTES + list(special_tokens.keys())
                                                                           ^^^^^^^^^^^^^^^^^^^
AttributeError: 'list' object has no attribute 'keys'

...snip...
 + mlx==0.30.0
 + mlx-lm==0.28.4
 + mlx-metal==0.30.0
 + mlx-vlm==0.3.9
...snip...

Similar error in mlx-vlm, so maybe it's MLX or the model itself.

[taoeffect]

Is there a single MLX version of this model that works? I ran into another error trying load a different one:

Error when loading model: ValueError: Tokenizer class TokenizersBackend does not exist or is not currently imported.

Same as #1289

[vdavid]

I tried https://huggingface.co/mlx-community/Devstral-Small-2-24B-Instruct-2512-4bit on an M1 Mac, also got an "Error when loading model: ValueError: Tokenizer class TokenizersBackend does not exist or is not currently imported.". No idea how to solve this.