I am a paid ChatGPT subscriber for more than one year, and this issue has now blocked my professional workflow for 4+ consecutive days.
Failure Uploaded ZIP/CSV/source files may appear normally in ChatGPT, but Python/container execution either cannot access them or fails immediately with:
ClientError
Encountered exception: <class ‘caas.internal.errors.ClientError’>
In some sessions even trivial Python execution fails before any file-processing logic runs.
What I have reproduced
Project chats fail intermittently.
Non-Project chats have also started failing intermittently.
The exact same files have worked in other runtime sessions/accounts.
In one working session, 12/12 ZIP archives successfully opened and passed CRC/integrity checks, so the archives themselves are not corrupt.
The issue can temporarily recover and then fail again.
Different devices/browser/app testing did not resolve it.
OpenAI Support case #14187763 already has HAR data, timestamps, screenshots, cross-device/cross-account testing and other diagnostics. Support has stated that no additional user-side troubleshooting is required.
Possible engineering checks — hypotheses, not claimed root cause
Force provision a completely fresh execution sandbox/container.
Invalidate stale runtime/session and attachment-materialization/mount state.
Re-route affected sessions/accounts to a fresh execution worker/pool.
Inspect the internal request immediately preceding caas.internal.errors.ClientError, especially failures occurring before Python/container startup.
Verify execution provisioning/entitlement against a known-good account/session.
If possible, recreate affected Project runtime state while preserving Project data.
Validate any fix with multiple consecutive Python + ZIP/file-read tests, because a single successful attempt does not prove recovery.
This is not a minor upload inconvenience. My work depends on Python, large trading datasets, ZIP/CSV processing and source-code modification. Without the execution environment, my production workflow cannot proceed.
Other users appear to be reporting the same /mnt/data / attachment-materialization / runtime behavior. If you are still affected, please add whether Python itself fails, whether regular chats vs Projects differ, and whether the problem temporarily recovers and then returns.
