Detect known incompatible Azure CLI extensions that should be removed.

Question

Detect known incompatible Azure CLI extensions that should be removed.

Joe Comeau 40

The error message is not very verbose on what extensions should be removed

We cannot go thru with the update process on this.

Update: 12.2601.1002.503

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Bharath Y P 9,385 Reputation points Microsoft External Staff Moderator

2026-05-14T18:28:53.52+00:00

Hello Joe Comeau,

thank you for posting your query on Microsoft Q&A platform.

We are looking into your issue and will keep you posted updates.

Thanks.
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-05-15T00:13:52.2366667+00:00
Azure Update Manager (ARBStack) runs before applying updates, and the error message unfortunately doesn't tell you which extension to remove. Let me walk you through how to fix it.

Azure Update Manager validates a set of readiness conditions before proceeding with an update. One of those checks flags Azure CLI extensions installed on the machine that are no longer compatible with the current platform version. Until those extensions are removed, the update process is blocked.

List your currently installed Azure CLI extensions
Run the following on the affected machine (AFNODE001 based on your screenshot):

az extension list --output table

This will show you everything currently installed. Look for any older or deprecated extensions — common culprits include older versions of azure-devops, connectedmachine, arcappliance, or any Arc-related extensions that may have since been folded into the core CLI.

Remove the incompatible extensions

Once you identify the problematic extension(s), remove them:

az extension remove --name <extension-name>

If you're unsure which specific one is flagged, you can try removing extensions one at a time and re-running the Update Manager prereq check after each removal, or remove all non-essential ones temporarily.

Update the Azure CLI itself

While you're at it, make sure the CLI is on the latest version. Outdated CLI installs are often the root cause of extension incompatibility:

az upgrade

This will also update all currently installed extensions to their latest compatible versions.

Retry the Update Manager operations

Once the incompatible extension(s) are cleared, go back to Azure Update Manager and re-trigger the update for the affected node. The prereq check should pass this time.

https://learn.microsoft.com/en-us/cli/azure/azure-cli-extensions-overview
https://learn.microsoft.com/en-us/cli/azure/update-azure-cli
https://learn.microsoft.com/en-us/azure/update-manager/troubleshoot
https://learn.microsoft.com/en-us/azure/update-manager/prerequisites

Thanks.
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-05-22T18:58:26.2766667+00:00

Hello @Joe Comeau

I wanted to check if my last response made sense. I’d be glad to assist further or explain anything in more detail and please accept as Yes and upvote if the answer is helpful so that it can help others in the community.
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-05-26T02:14:30.3933333+00:00

Hello @Joe Comeau

I wanted to check if my last response made sense. I’d be glad to assist further or explain anything in more detail and please accept as Yes and upvote if the answer is helpful so that it can help others in the community.
Joe Comeau 40 Reputation points

2026-05-27T16:23:00.16+00:00

Hi Manish,

Are you able to tell which one is the extension that is causing the problem?
Would it be okay to just remove all the extensions?

Apologies for the delayed response

Best,

Andy (Working on this on behalf for Joe)
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-05-29T19:19:33.7133333+00:00
Hello @Joe Comeau

Thanks for sharing the output that makes it a lot easier to narrow down.

Looking at your list, the most likely offender is arcappliance (1.6.0). The ARBStack readiness check is specifically tied to Arc Resource Bridge operations, and an installed arcappliance CLI extension that doesn't align with the version the platform expects for the incoming update (12.2601.1002.503) is a very common trigger for this exact critical error. I'd also flag connectedmachine (1.0.0) as a secondary suspect version 1.0.0 is quite dated and is a known culprit in environments that have been around for a while.

Try removing arcappliance first

az extension remove --name connectedmachine

Would it be okay to just remove all the extensions?
Regarding your question about removing all extensions is yes, that is safe in this context.

All four of your extensions live under C:\CloudContent\AzCliExtensions\, which is the platform-managed directory. The update process itself will reinstall the correct compatible versions during the update run.

Removing them won't affect your running VMs or workloads it only temporarily removes CLI management capability for things like Arc VM operations and Arc appliance commands until they're restored post-update.

If you want to take the fastest path, you can remove all four in one go:

az extension remove --name arcappliance az extension remove --name connectedmachine az extension remove --name customlocation az extension remove --name stack-hci-vm

Then retry the update. The platform will bring back the right versions as part of the update.

One more thing worth doing while you're at it — make sure the CLI itself is on the latest version:

az upgrade

Outdated CLI installs are a frequent root cause of extension incompatibility, so this helps prevent the same issue from coming back on the next update cycle.

Links for reference :

ARBStack update troubleshooting:
https://learn.microsoft.com/en-us/azure/azure-local/update/update-troubleshooting-23h2

Azure CLI extension management:
https://learn.microsoft.com/en-us/cli/azure/azure-cli-extensions-overview

Arc resource bridge troubleshooting:
https://learn.microsoft.com/en-us/azure/azure-arc/resource-bridge/troubleshoot-resource-bridge

Azure Update Manager prerequisites:
https://learn.microsoft.com/en-us/azure/update-manager/prerequisites

Thanks,
Manish.
Joe Comeau 40 Reputation points

2026-05-29T21:41:15.76+00:00

Hi Manish,

After removing the extensions the update has still failed.

Any information would be great

Best.

Andy (Working on behalf of Joe)
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-06-01T09:29:23.13+00:00

Hello @Joe Comeau / Andy

I have requested for few details over the private message pls respond at your earliest.

1 answer

Your answer

Bharath Y P 9,385 Reputation points Microsoft External Staff Moderator

2026-05-14T18:28:53.52+00:00

Hello Joe Comeau,

thank you for posting your query on Microsoft Q&A platform.

We are looking into your issue and will keep you posted updates.

Thanks.
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-05-22T18:58:26.2766667+00:00

Hello @Joe Comeau

I wanted to check if my last response made sense. I’d be glad to assist further or explain anything in more detail and please accept as Yes and upvote if the answer is helpful so that it can help others in the community.
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-05-26T02:14:30.3933333+00:00

Hello @Joe Comeau

I wanted to check if my last response made sense. I’d be glad to assist further or explain anything in more detail and please accept as Yes and upvote if the answer is helpful so that it can help others in the community.
Joe Comeau 40 Reputation points

2026-05-27T16:23:00.16+00:00

Hi Manish,

Are you able to tell which one is the extension that is causing the problem?
Would it be okay to just remove all the extensions?

Apologies for the delayed response

Best,

Andy (Working on this on behalf for Joe)
Joe Comeau 40 Reputation points

2026-05-29T21:41:15.76+00:00

Hi Manish,

After removing the extensions the update has still failed.

Any information would be great

Best.

Andy (Working on behalf of Joe)
Manish Deshpande 6,835 Reputation points Microsoft External Staff Moderator

2026-06-01T09:29:23.13+00:00

Hello @Joe Comeau / Andy

I have requested for few details over the private message pls respond at your earliest.

Answer 1

Azure Update Manager is blocking the update because at least one Azure CLI extension installed on the node is on a “known incompatible” list for that update. The readiness check, however, doesn’t enumerate which one, so the unsupported extensions must be identified and removed manually from the node’s Azure CLI.

Use the Azure CLI extension management commands on the affected node (AXNODE01 in the screenshot):

List all installed extensions
```
   az extension list --output table
```
This shows every extension currently loaded into the Azure CLI on that node.
Remove non-required or suspect extensions For each extension that isn’t required for Azure Stack HCI / Azure Local operations, remove it:
```
   az extension remove --name <extension-name>
```
If an extension was installed from a custom source and is not in the official list of Azure CLI extensions, it is a strong candidate for removal.
If an extension was installed manually on disk If an extension doesn’t remove cleanly, delete it from the extension directory on the node:
- On Windows (default path): %USERPROFILE%\.azure\cliextensions
- On Linux/macOS: $HOME/.azure/cliextensions
Or, if AZURE_EXTENSION_DIR is set, delete the subfolder for the extension from that directory.
Re-run the readiness check After removing nonessential extensions, re-run the Azure Update Manager readiness checks for the 2026.01 cumulative update. If the error persists, continue pruning extensions until only the core, required ones remain.
Keep extensions updated and aligned with the base CLI For any extensions that must remain, ensure they are up to date and compatible with the Azure CLI version on the node:
```
   az extension update --name <extension-name>
```
If a command previously provided by an extension now exists in the base CLI, uninstall the old extension and rely on the built-in command set.

This process systematically removes unsupported or obsolete Azure CLI extensions so the “ARBStack Azure CLI Known Incompatible Extensions” readiness check can pass and the update can proceed.

References:

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Detect known incompatible Azure CLI extensions that should be removed.

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