thanks for the quick reply. I tried restarting, but to no avail. I also updated Docker to the most recent, but it persisted. I am working on a Mac Sierra, which might have to do with it.
Will retry periodically, and perhaps on other machines - couldn’t find anything related in issues/stackoverflow though. If sb runs into solution, I’d be grateful.
Otherwise I’ll try to work around …As far as I understand, I should be able to copy a singularity image prepared by sb else to the cluster where I intend to use it, right?.. But getting that to run (it complains about bindings of folder from the cluster’s filesystem) is a different challenge…
thanks & best ralf.