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[Bug]: container daemon hangs when container cp from a mounted volume #1873
Description
I have done the following
- I have searched the existing issues
- If possible, I've reproduced the issue using the 'main' branch of this project
Steps to reproduce
- Create a named volume:
container volume create some-vol - Start a temporary container to transfer data:
container run -d --name temp-importer -v some-vol:/target alpine tail -f /dev/null - Now depending on the src/dst setup the behavior is different.
Volume as dst: copy from the host to the mounted volume
container cp /path/to/host/src temp-importer:/target
The command didn't seem to have any effects even with --debug option.
- No output from CLI
- No files in the
/targetfolder of the temp container (except forlost+found)
Volume as src: copy from the mounted volume to the host
Then I did another test the other away around.
After manually creating a file with touch /target/hi in the temp container, I tried to copy from the mounted volume to the host:
container cp temp-importer:/target/hi /path/to/host/dst
The command was stuck and the daemon simply became unresponsive afterwards.
Problem description
I was initially trying to migrate some data from the host to a volume created with container, and found out container cp didn't work once a mounted volume is involved, either as source or destination.
- no-ops when copying from the host to the mounted volume
containerdaemon hangs when copying from the mounted volume to the host
Logs
Can't locate any logs.
❯ container system logs --debug
Filtering the log data using "subsystem ==[cd] "com.apple.container""
Timestamp Thread Type Activity PID TTL
--------------------------------------------------------------------------------------------------------------------
Log - Default: 0, Info: 0, Debug: 0, Error: 0, Fault: 0
Activity - Create: 0, Transition: 0, Actions: 0
Environment
- OS: macOS 26.5.1 (25F80)
- Xcode: N/A
- Container: Container CLI version 1.0.0Code of Conduct
- I agree to follow this project's Code of Conduct
Activity
Jakeshadow commentedon Jul 1, 2026
This is a known limitation —
container cpdoesn't handle Virtualization.framework's filesystem passthrough reliably for mounted volumes. Until it's fixed, the workaround is to usecontainer execwith a direct copy command inside the container:For migrating data into a new container, you can also use a shared bind mount as an intermediate: mount the same host directory in both containers, then copy from within. Full migration guide covering this and other gotchas: https://maccontainer.dev/compose-alternative/
magnimodi commentedon Oct 13, 2026
Additional data point: still reproducible on 1.5.0, also affects bind mounts (virtiofs), and the data silently lands in the rootfs layer underneath the mountpoint.
Reproduced on container CLI 1.5.0 (brew), macOS 27.0.1 arm64, alpine:latest.
Same with
-v /host/dir:/dane(virtiofs): cp returns 0, file absent in the container and on the host, but present incontainer exportoutput.Control:
container cp plik.txt b:/tmp/plik.txtworks.tar -c plik.txt | container exec -i b tar -x -C /daneworks.Expected: cp resolves the path as the running container sees it (through mounts), or fails with a non-zero exit code.
Actual: exit 0 and data silently lands in the masked rootfs directory; copy out of mounted paths fails with notFound (on 1.5.0 the daemon no longer hangs).
Log: only
copyIn xpc handler [uuid=b], no error.Stream file transfers on mounted paths through exec (#27) (#32)