ImportError: cannot import name 'container_abcs' from 'torch._six'

How to fix ImportError: cannot import name 'containerabcs' from 'torch.six'

The library importing torch.six is too old for your torch. `torch.six.containerabcs was removed in torch 1.9; the modern equivalent is collections.abc. Upgrade the offending package (apex, pytorch-lightning, mmcv), or patch its import to import collections.abc as containerabcs`. Your torch is fine; the caller is stale.

The exact error

ImportError: cannot import name 'container_abcs' from 'torch._six'

Fix it

1. Read the traceback: find which file does from torch._six import container_abcs (often apex/amp/ampstate.py or pytorch_lightning).

Expected: you have the stale file path

1. Preferred: upgrade the stale package (pip install -U [package], or reinstall apex from current master).

Expected: the import line is gone or fixed upstream

1. If you must patch: replace from torch._six import container_abcs with import collections.abc as container_abcs and reinstall that package.

Expected: import works on torch>=1.9

When this applies

the traceback shows from torch._six import container_abcs failing on torch 1.9+

When this does NOT apply

torch itself fails to import (DLL/shared-library errors) - that is an install problem, not this

Versions

torch >= 1.9 with old apex / pytorch-lightning / mmcv

Why it happens

torch removed the private _six compat module in 1.9; downstream libs pinned to the old private API.

Edge cases

Downgrading torch below 1.9 'fixes' it too, but breaks everything else modern; upgrade the caller instead.