ACR Purge Does not seem to have a way to purge only untagged images.

[groogiam]

Describe the bug
I'm running the following command to try to purge just untagged ACR images.

az acr run --registry myregistry--cmd "acr purge --filter 'myrepo:.*' --ago 300000d --untagged" /dev/null

The ago is set so high so no tagged images are deleted based on the documentation here.

https://learn.microsoft.com/en-us/azure/container-registry/container-registry-auto-purge

Note
The --untagged filter doesn't respond to the --ago filter. For additional parameters, run acr purge --help.

This used to work, but at some point in the recent passed it stopped. My untagged image manifests are just piling up in the ACR causing me to be charged for storage that I don't need. There does not seem to be a way to simply purge untagged images anymore.

To Reproduce
Steps to reproduce the behavior:

1. Run the command above with an ACR that has 1 tag and multiple untagged manifests.
2. No manifests will be deleted

Number of tags to be deleted: 0
Number of manifests to be deleted: 0
2026/02/18 04:45:57 Successfully executed container: acb_step_0
2026/02/18 04:45:57 Step ID: acb_step_0 marked as successful (elapsed time in seconds: 0.850325)

Expected behavior
Untagged manifests should be deleted.

Screenshots
See output from the command run against and ACR with this showing in the portal

Any relevant environment information

• OS: Windows 11
• azure-cli 2.83.0

Additional context

[FeynmanZhou]

@groogiam acr purge CLI tool released v0.18 which introduced a new flag --untagged-only by #489. This release has been rolled out to all public regions of ACR. Can you try it again in ACR purge tasks?

[groogiam]

@FeynmanZhou I was able run the command below without error.

acr purge --filter 'myrepo:.*' --ago 1d --untagged-only --dry-run

I also tested this command. This is what I recently updated to while waiting for the --untagged-only to be deployed.

acr purge --filter 'myrepo:^$' --ago 1d --untagged --dry-run

It appears these two commands should have the same result, can you confirm this?

Thanks.