@jurgenhaas _Context_ I got MacOS running with `v1.8.2-mac0.2` . For MacOS to work with the ssh agent, we had to mount a magic ssh socket introduced in a newer Docker version. **Issue** With the newest update to dynamically get the User and Group, the User/Group doesn't get transfered properly to the Docker container on MacOS like before. Therefore, the permissions in the created Docker container aren't correct. The issue is that the User id, in my case `501`, isn't set in the `etc/passwd`, where the tools in the Docker container are looking it up. That's actually not a fault by Docker or our scripts because even on my main system, this id can't be found in `etc/passwd`. So nothing gets lost underway. This is a helpful resource to understand the problem. https://unix.stackexchange.com/questions/241927/why-mac-os-x-does-not-set-uid-bit-for-usr-bin-passwd I found a solution in [this GitHub thread](https://github.com/databio/bulker/issues/30) where the maintainer mentioned that on MacOS, everything (User/Group) gets automatically inherited from the Docker engine (VM) correctly, so modifying can only make it worse. I tested this with removing the `--user` flag and the user / group `--env` variables and it works! The working final code is in `v1.8.2-mac0.3` .