Azure CLI 2.51.0 (August 01, 2023) introduces Python UserWarning of cryptography for extensions

TL;DR

The warning means the 32-bit Azure CLI is running on 64-bit Windows. Fix: migrate to the 64-bit Azure CLI (see the install docs section 'Migrate to 64-bit Azure CLI'). GitHub-hosted runner images now ship 64-bit by default, so updating the runner image also resolves it.

The error

UserWarning: You are using cryptography on a 32-bit Python on a 64-bit Windows Operating System. Cryptography will be significantly faster if you switch to using a 64-bit Python.

In Azure Pipelines this surfaces as a PowerShell RemoteException that fails the pipeline, typically when using the arcappliance extension.

Fix it

1. Confirm you are on the 32-bit CLI:

   az version

Success check: the installed CLI is 2.51.0 (or nearby) and the warning mentions 32-bit Python.

1. Migrate to the 64-bit Azure CLI per the install docs ('Migrate to 64-bit Azure CLI').

Success check: reinstall completes; az version no longer triggers the warning.

1. If you run on GitHub-hosted agents, update to a current runner image, which ships 64-bit by default.

Success check: the pipeline step passes with no RemoteException.

1. As a short-term workaround, pin Azure CLI to 2.50.0 where the warning does not appear.

Success check: pipeline goes green, but treat this as temporary.

When this applies

• Azure CLI 2.51.0 on 64-bit Windows emitting the cryptography 32-bit UserWarning.
• Azure Pipelines failing with PowerShell RemoteException tied to the warning (arcappliance extension).

When it does not apply

• You are already on the 64-bit CLI and still see warnings; the cause is different.
• Non-Windows agents, or warnings from a different Python package.
• Cryptography is genuinely slow for workload reasons rather than the 32-bit build.

Compatibility

• Azure CLI 2.51.0 (August 2023) 32-bit Windows build. Fixed by migrating to 64-bit.
• GitHub-hosted runners: current images ship 64-bit.

Variant phrasings

• Azure CLI 2.51.0 cryptography UserWarning 32-bit Python
• arcappliance extension RemoteException Azure Pipelines
• "You are using cryptography on a 32-bit Python on a 64-bit Windows"

Why it happens

Azure CLI 2.51.0 shipped a 32-bit Python runtime on 64-bit Windows. The cryptography package detects the mismatch and warns; in PowerShell remoting contexts the warning becomes a RemoteException that fails the pipeline. The 64-bit CLI build removes the mismatch entirely.

Edge cases

• Self-hosted agents need the manual 64-bit migration; only GitHub-hosted images updated automatically.
• Extensions other than arcappliance can trigger the same warning; the fix is identical.
• Source: https://github.com/Azure/azure-cli/issues/27115